All the recent Crocodilia possess two pairs of skin-glands, both secreting musk. One pair is situated on the throat, on the inner side of the right and left half of the lower jaw. The opening of the gland, visible from below (see the figure of Crocodilus niloticus, p. 461), is slit-like, and leads into a pocket, which in large specimens is of the size of a walnut; the bag is filled with a smeary pale brownish substance, a concentrated essence of musk, much prized by natives. The secretion is most active during the rutting time, when the glands are partly everted. My young Crocodiles and Alligators often turned them inside out, like the finger of a glove, when they were taken up and held by force. The other pair lies within the lips of the cloacal slit, and is not visible from the outside. The use of these strongly scented organs, which are possessed by both sexes, is obviously hedonic. The sexes are probably able to follow and find each other, thanks to the streak of scented water left behind each individual.

The tongue is flat and thick, attached by its whole under-surface, so that it can be elevated but not protruded. It fills the whole space between the two halves of the lower jaw behind their symphysis. The dorsal surface shows numerous irregular polygonal fields, in the middle of most of which opens the duct of a large mucous gland. Tactile and gustatory corpuscles are scattered over the surface in the shape of tiny wartlike elevations. The hinder margin of the tongue is raised into a transverse fold, which, by meeting a similar fold from the palate, the velum palatinum, can shut off the mouth completely from the deep and wide cavity of the throat, which leads of course into the gullet. Dorsally the choanae open into this cavity; and since the narial passages are transformed into long tubes, completely surrounded by bone, Crocodiles can lie submerged in the water, with only the nostrils exposed and with the mouth open, and breathe without water entering the windpipe. The opening of the latter, the glottis, is a longitudinal slit, protected by the laryngeal cartilages, opened and closed by muscles. There is also a pair of membranous folds within the glottis, which serve as vocal cords. Ventrally below the larynx lies the cartilaginous, broad, shield-shaped hyoid; on the sides are attached the short hyoid horns. The trachea is long, consists of about sixty or more complete cartilaginous rings, and divides into two short bronchi, likewise protected by complete rings. The trachea is depressed; its transverse diameter decreases from the glottis backwards. The lungs have attained a high degree of efficiency. Each lung is an oval sac, and is transformed into a complicated system of tubes, at the end of which are the countless honeycomb-like respiratory cells, the whole lung being spongy. The main bronchus is continued straight down to the posterior end of the lung, and sends off during its course regular secondary bronchi, and these send off tertiary bronchi. The whole arrangement is very regular, the tubes coming off like rows of organ-pipes. Each lung hangs freely in the thoracic cavity. Besides its ventral attachment by its arteries, veins, and the bronchus, it is connected by loose tissue with the liver and the pericardial septum. Each half of the thoracic cavity is partitioned off from the abdominal cavity by a strong transverse mesenteric lamella. The partition between the lungs and the stomach is at first simple, it then divides, to enclose the liver; the anterior partition passing between liver and lung to the inner surface of the sternum; the posterior lamella between the liver and the stomach. Both meet on the ventral surface of the liver, and are continued into or attached to the peculiar "diaphragmatic" muscle. This is covered by the internal rectus muscle of the abdomen, arising from the last pair of abdominal ribs near the pubic bones; it is innervated by a branch of the last precrural nerve, and extends as a broad but thin muscular sheath (always within and unconnected with the abdominal wall) to the ventral posterior vein of the liver; thence it is continued as an aponeurosis, together with the peritoneal lamella mentioned above, to the inner surface of the sternum. Contraction of this singular muscle indirectly widens the pulmonary cavity, and thereby directly aids inspiration. It acts consequently like the diaphragm or midriff of Mammals, although it is morphologically an entirely different muscle.

The stomach is smaller than one might expect from the fact that large Crocodiles can eat up nearly a whole man; but a great deal of their prey is stowed away preliminarily in the wide gullet until the rapid, powerful digestion, which dissolves every bone, makes room in the stomach. This consists of a wide, somewhat globular gizzard, rather muscular, with a pair of tendinous centres like those of birds, and a much smaller pyloric, globular, more glandular compartment. It leads into the duodenum, which is coiled up into a double loop, and receives at its end the hepatic and pancreatic ducts. The small intestine is narrow, and is stowed away in a few irregular coils; the rectum is wide; a caecum is absent.

The cloaca is peculiar. The coprodaeum and urodaeum, cf. p. 498, are confluent, and form a wide, oval bag, closed in front and behind by strong sphincters, and it acts normally as a urinary receptacle. In the dorsal wall open the two ureters; a little towards the sides, and ventrally, open the two oviducts, on the right and left, near the base of the clitoris. Then follows a transverse, soft, muscular fold, which shuts off this cavity from the proctodaeum or outermost chamber. In the latter is stowed away the rather large copulatory organ. It arises out of the medio-ventral wall of the cloaca, and has a deep, longitudinal groove on its morphologically dorsal side for the conduction of the sperma, the vasa deferentia opening near its basal end. On either side of the root of this organ, in both sexes alike, opens a peritoneal canal, wide enough in large specimens to pass a goose-quill. The outer opening of the cloaca forms a longitudinal slit; within it, dorso-laterally, are the openings of the two anal musk-glands.

The kidneys are much lobed. The testes are long and oval; the ovaries are much elongated and flat; and the eggs contained therein in great numbers are extremely small, except those which ripen during the time of propagation.

The vascular system has attained the highest state of development of all reptiles. The heart is practically quadrilocular, the partition between the right and left ventricle being complete; but there is still a small communication, the foramen Panizzae, which lies in the middle of the wall common to both aortae, where they leave their respective ventricles. The left aortic arch conveys all the arterialised blood out of the left ventricle, and supplies head, neck, trunk, and tail. The right aortic arch, coming from the right ventricle, supplies venous blood, mixed with what little arterial blood it receives through the foramen Panizzae, to most of the viscera. On a level with the stomach both descending aortic arches are still connected with each other; the left aorta supplies most of the gut; the right, the trunk and the kidneys.

The outer ear lies in a recess, dorsally overhung by the lateral edge of the bony squamoso-postfrontal bridge; and this carries a flap of skin, provided with muscles, to close the ear tightly. The tympanic membrane is visible at the bottom of the recess; shining through it is part of that cartilage which is homologous with the malleus of the auditory ossicular chain; the outward extension of the latter on its way to the mandible, behind the joint, passes as a partly cartilaginous string through the slit-like hole which is visible at the back of the skull, between the quadrate and the latero-occipital wing.

The eyes have, besides the lower and upper lid, a third, the nictitating membrane, which can be drawn over the front of the eyeball. In the upper lid lies a cup-shaped bony plate of variable size. The pupil contracts into a vertical slit. The iris is greenish.

The recent geographical distribution of the various kinds of Crocodilia loses its mystery when we recollect that during the Tertiary period Alligators, Crocodiles, and long-snouted Gavials existed in Europe. The solitary species of Alligator in China is the last living reminder of their former Periarctic distribution. The group, taken as a whole, is otherwise now intertropical, Crocodiles alone inhabiting the Palaeo-tropical region, together with long-snouted forms in the Oriental sub-region, while Alligators and Caimans, with a few Crocodiles, live in America.

They are all rapacious, doing much damage by their predatory habits, and are fierce and sulky in temper. But the danger to man differs much in different countries. While Crocodiles are dreaded in some localities, they are in others considered almost harmless, and men swim through the haunted waters without hesitation. It seems as if certain old and wily individuals turn into man-eaters, just like tigers and lions.

Their home is the water, in which they pass the night, their time of hunting. The prey is either patiently watched or stalked, and nothing falls amiss. Water-birds are seized by the beast, which rises imperceptibly from below. Some species are said to make use of their powerful tails for hitting the victim and even jerking it into the mouth. The strength of their jaws is enormous, and they do not let go what they have seized, unless, in the case of a man, he has the presence of mind and the opportunity to dig his fingers into the monster's eyes whilst being dragged down.

In the morning they crawl on to sandbanks, or on to logs of wood, which they closely resemble, in order to bask, mostly in such a position that on the slightest alarm they can plunge into the water. For this reason they frequently make a half circle before they settle down to rest, with the heads turned towards the river. There they bask all day long, apparently fast asleep, often with gaping mouths. But their sense of hearing and of sight is sharp, and they learn from experience, old individuals being by far the most wary. Commercially the skins are now of considerable value. The flesh is white, and is tolerable eating but for the combination of fishy and musky odour, which, although faint, is not to everybody's liking.

All the species have a voice, a kind of loud, short bark or croak, heard at night and when angered. The female lays several dozen or even three score white, oval, hard-shelled eggs in the sand, well out of the reach of moisture; and some species construct an elaborate kind of nest. The mother watches it, takes care of and fights for her offspring, numbers of which fall an easy prey to large storks, fishes, and to the stronger members of their own kind.

In the cooler countries they hibernate in the ground; and in hot countries, which are subject to drought, some kinds aestivate in the hardened mud; or they migrate. When during a prolonged drought on the island of Marajó, at the mouth of the Amazon, the swamps and lakes were dried up, the Alligators migrated towards the nearest rivers, and many perished in the attempt. On one farm were found 8500 dead, and at the end of Lake Arary more than 4000. Such occurrences in bygone times may perhaps explain the masses of bones found here and there in a fossil state.

The age to which Crocodiles can live is quite beyond calculation. They are capable of propagation long before they are anything like half-grown, maybe at an age of little more than ten years; then they continue to grow perhaps for more than one hundred years, until they die.

It is customary to divide the Eusuchia, most of which are extinct, into a longirostral and a brevirostral section. In the former the snout is much elongated and narrow, and the nasal bones, although they are sometimes very long, do not reach the nasal groove. The mandibular symphysis is very long, and is formed not only by the dentary but also by the splenial bones. In the brevirostral section the snout is shorter, sometimes broad and rounded off, and the nasal bones are supposed to reach the nasal groove, or at least to approach it very nearly; the mandibular symphysis is formed by the dentaries only. But these distinctions are quite arbitrary, and there exist all kinds of intermediate forms. For instance, in Goniopholis and Diplocynodon, which are both undoubtedly near allies of the recent Crocodiles and Alligators, the nasal bones are considerably removed from the nasal groove; and in Crocodilus cataphractus they are separated even from the premaxilla by the medio-dorsal suture of the maxillaries. Again, in Goniopholis the mandibular symphysis is so long that it comprises part of the splenial bones. Both typically long- and short-snouted forms occur already in the Upper Oolite, but in the Lower Jurassic age only long-snouted kinds seem to have existed. The latter cannot easily be connected with Belodon, one of the Parasuchia, on account of the position of the nostrils; the mere shortening of the long premaxillaries of Belodon would not transfer its distinctly paired nostrils to the anterior end of the premaxilla. To account for the position of the nasal groove in the Eusuchia, we have to go back to a primitive condition, such as that of the Pseudosuchian Aëtosaurus, and this consideration shows that the Parasuchia and Eusuchia are collateral branches.

The Eusuchia have been split into many families. Zittel, for instance, divides them into ten, some of them on insufficient grounds, since there are too many intermediate forms; and more, sometimes quite unexpected, modifications are still being found. Several of the accepted families represent collateral or convergent lines of development.

There is the same tendency to transfer the choanae further back, owing to the formation of a solid secondary roofing in of the mouth, to transform the amphicoelous into procoelous vertebrae, to reduce the supratemporal foramina, and to obtain a better development of the dorsal armour, whilst that on the ventral side is gradually reduced. Lastly, there is a tendency towards a shortening and broadening of the snout, a condition which has reached its culmination in the Alligators, while the Gavials are survivals of another branch. The notches in the premaxilla, for the reception of some of the lower teeth, have also been acquired independently. Although the recent Crocodilia cannot now, as has been pointed out by Boulenger, be separated into different families, no valid diagnoses being possible owing to the existence of Tomistoma, their phylogeny shows them to belong to at least two heterogeneous groups.

Key to the Genera of recent Crocodilia.

Fam. 1. Teleosauridae, in the Lias and Oolite of Europe; marine.–Snout very long and slender. Nasals widely separated from the premaxillae by the maxillaries. Choanae at the posterior end of the palatines. In front of the eye a small sub-lacrymal foramen. Supratemporal foramina large. Vertebrae amphicoelous. Anterior limbs scarcely half as long as the posterior pair. The dermal armour consists of two rows of broad scutes on the back, while the belly is protected by a shield of numerous bony scutes, which are connected with each other by sutures. Teeth numerous and rather slender. General appearance like that of Gavials.

Teleosaurus of the Middle and Upper Oolite in England and France. Snout very slender. Nasals narrow and short. The under side is protected by a beautifully finished armour, consisting of a square breast-shield of four rows of bony scutes, and a larger, long, oval shield on the belly, with about six longitudinal and seventeen transverse rows of scutes.

Mystriosaurus, of the Upper Lias in France and Germany, reached a length of 15 feet, and is characterised by an additional series of keeled but smaller caudal plates running parallel with the middle pairs, which are neatly sutured together.

Fam. 2. Metriorhynchidae, in the Upper Oolite of Europe; marine.–Nasals broad posteriorly, sometimes extending with a pointed wedge very near the premaxillae. Without sub-lacrymal foramina. Eyes with a ring of ossifications in the sclerotic. Dermal armour unknown. Vertebrae and choanae like those of the previous family. Metriorhynchus and Geosaurus.

Fam. 3. Macrorhynchidae, in the freshwater deposits of the Purbeck, Wealden, and Greensand of Europe. Snout long and slender. The nasals are narrow, and so elongated that they meet a similar long extension of the premaxillaries. Choanae between the palatines and pterygoids. Vertebrae amphicoelous. Dermal armour consisting of two imbricating dorsal and eight ventral rows, e.g. Pholidosaurus of the English Wealden.

Fam. 4. Gavialidae.–Snout long and slender. The choanae are situated entirely within the pterygoids. Vertebrae procoelous. Members of this family make their first appearance in the littoral marine deposits of the Upper Chalk of Europe and North America; others are common in tertiary, marine, and freshwater deposits, whilst only two genera and species occur now in the Oriental sub-region.

Thoracosaurus in the Upper Chalk of New Jersey and France and Belgium is intermediate between Gavialis and Tomistoma. The prefrontal bones are very small, while the lacrymals are very long and surround the nasals posteriorly. The nasals themselves are slender, and reach the posterior likewise long and narrow prolongations of the premaxillaries.

Gavialis.–The snout is extremely long and slender. The mandibular symphysis is so long that it comprises a great portion of the splenial bones, and extends backwards almost to the level of the last teeth and to the palatal foramina. The nasal bones are very short, and are separated from the premaxillaries by the long suture of the maxillaries. About twenty-eight upper and twenty-five lower teeth on each side.

G. gangeticus, the only recent species, is essentially Indian, inhabiting chiefly the basins of the Ganges, Brahmaputra, and Indus; it occurs also in the Mahanadi of Orissa and in Arakan, but does not live in the Irrawaddy, nor in the Narbada, Kistna, and farther south. In spite of its great size, which reaches 20 feet or even more, it is harmless, and lives entirely upon fish; hence its Hindustani name, gharial, meaning fish-eater, of which the generic name is a corruption.

The nuchal and dorsal scutes form a continuous shield, but there are two small postoccipital scutes. General colour, dark olive-brown above; the young are paler, with dark markings. The male is remarkable for several peculiarities. The nose is very much swollen, and can be inflated like a bag when the nostrils are closed. In connexion herewith, probably produced by the recoil of the air in the long narial passages towards the choanae or posterior nares, there is a pair of hollow globular swellings, in large specimens of the size of a goose's egg. The shell of these globes is formed by the dorsal wings of the palatine bones above the floor of the choanae, and they extend forwards to the right and left of the ethmoid almost to the vertical downward process of the prefrontals.

Although the Gharial is common enough, we know next to nothing about its habits, and in zoological gardens it is rather rare. A. Anderson^[139] has, however, made the following observations. Forty eggs were dug out of the sand, where they were lying in two tiers, twenty below and twenty above, with a foot of sand between. The young ran with amazing rapidity the moment they were hatched. Some of them actually bit his fingers before he had time to remove the shell from their bodies! The length of these new-born creatures was 15 to 16 inches, 9 of which belonged to the long and slender tail.

Several fossil species have been described from the Pliocene deposits of the Sivalik Hills of India; and in the same district occurred the closely allied Rhamphosuchus crassidens, which reached the gigantic length of about 50 feet!

Tomistoma.–The general configuration of the skull and snout is that of Gavialis, but the nasal bones are long and reach the premaxillaries, although not the nasal groove, thereby separating the maxillaries. The first and fourth mandibular teeth fit into notches of the upper jaw, while most of the others fit into pits between the teeth of the upper jaw. About twenty upper and eighteen lower teeth on each side.

T. schlegeli, the only species, reaches a length of 15 feet; it inhabits the rivers and swamps of Borneo, Malacca, and Sumatra. Fossil specimens of Tomistoma have been found in the Miocene of Malta and Sardinia. Gavialosuchus of the Miocene of Hungary is closely allied.

Fam. 5. Atoposauridae.–The few members of this family, Atoposaurus, Alligatorium, and Alligatorellus, lived in the Upper Oolitic period of France, and were small, about one foot in length. The vertebrae are amphicoelous. The nasal groove is divided by a prolongation of the nasal bones. The head is short, and in its general shape rather like that of a lizard.

Fam. 6. Goniopholidae, in the Purbeck and Wealden of Europe and the corresponding level of North America. The vertebrae are amphicoelous. The choanae are still elongated but are situated between the palatines and pterygoids. The premaxillaries are rather large, and each sends a broad triangular process between the nasal and maxillary. The nasals are broad and are well separated from the nasal groove. The splenials help to form the mandibular symphysis.

Goniopholis.–The general configuration of the skull is rather like that of Crocodilus vulgaris. There is a pair of deep notches in the upper jaw for the reception of the lower canine teeth. G. simus and G. crassidens in England and continental Europe, and others in Colorado, were large-sized Crocodiles, some with a skull 2 feet in length. The dermal armour consisted of a pair of dorsal rows, a thoracic and an abdominal shield, composed as in the Teleosauridae of six to eight longitudinal sutured rows.

Fam. 7. Crocodilidae.–Beginning in the Upper Cretaceous period of Europe and North America, many forms of Crocodiles, Alligators, and Caimans existed in the Tertiary period in America, Europe, and India; persisting in Europe until the Plistocene. The vertebrae are procoelous. The choanae are completely surrounded by the pterygoids. The nasals reach the nasal groove, except in Crocodilus cataphractus. The orbits are larger than the small supratemporal fossae, and always continuous superficially with the lateral temporal fossae, the postfronto-jugal bridge not reaching the surface. The dorsal armour consists of more than one pair of longitudinal rows, while the ventral armour is much reduced in thickness or absent.

Diplocynodon.–Common in the Oligocene and Miocene of Europe, e.g. D. hastingsiae. The skull resembles that of the Alligators, but has a pair of lateral notches in the premaxilla for the reception of the third, and sometimes also of the fourth mandibular tooth. The ventral armour is still rather strong.

Crocodilus.–The fourth mandibular tooth fits, as a rule, into a notch in the upper jaw. The other teeth are more or less interlocked with those of the other jaw. The fifth upper tooth is the largest. The nasal bones form the posterior border of the nasal groove, but do not extend into it as a septum. The bony scutes of the dorsal shield are keeled, and stand closely together, being rarely united by suture; and they form from four to six principal rows.

Crocodiles have occurred since the Upper Chalk in Europe; many species existed in the Tertiary epoch in Europe and North America, decreasing in numbers in the Pliocene and disappearing with the beginning of the Plistocene. About ten recent species are known, and these have now a somewhat scattered distribution; namely, three species in Africa, one of them extending into Syria; three in tropical America and the West Indian Islands; the rest in the Malay, Indian, and North Australian countries.

C. palustris.–The "Mugger" of India. The premaxillo-maxillary suture is transverse, as in the Alligators. The adults retain the five teeth in each half of the premaxilla. The mandibular symphysis is short, extending only to the level of the fourth or fifth tooth. The snout is stout, rather broad; the top of the head is rough but without any ridges. The upper and lower jaw each contain nineteen teeth on either side. The nuchal scutes, six in number, are packed closely together, the four biggest forming a square. Four smaller scutes are arranged in a curved line on the occiput. The dorsal shield is composed of four, sometimes of six rows of larger scutes, of which the central pair is the broadest. The fingers are webbed at the base; the outer toes are broadly webbed, and the outer edge of the hind-limbs is turned into a serrated fringe. The general colour of the upper parts is dark olive-brown; the young are pale, with black spots. The length of twelve feet is considered a fair average size for a large specimen.

This, the "Marsh Crocodile," has a wide distribution. It inhabits the rivers, ponds, tanks, and marshes of India and Ceylon, extending eastwards through Burma and Malacca into most of the Malay islands, westwards into Beluchistan. This species is frequently venerated by the Hindoos, and is kept in a kind of domesticated condition, attended by fakirs. One of the most famous crocodile ponds, the so-called "mugger-peer," lies in an oasis of the sandy stretches to the north-west of Karachi. A. L. Adams has described a visit to this pond.^[140]

"The greater pond is about 300 yards in circumference, and contains many little grassy islands, on which the majority of the Crocodiles were then basking; some were asleep on its slimy sides, others half submerged in the muddy water, while now and then a huge monster would raise himself upon his diminutive legs, and waddling for a few paces, fall flat on his belly. Young ones, from a foot in length and upwards, ran nimbly along the margin of the pond, disappearing suddenly in the turbid waters as soon as we approached. The largest crocodile lives in a long narrow tank separated from the others. The fakirs, and natives who worship in the neighbouring temples, have painted his forehead red; they venerate the old monster, making a salaam to his majesty whenever he shows himself above water. A handsome young Beloochee, whose occupation it was to feed the animals, informed us that this specimen was upwards of 200 years old, and that by way of a 'tit-bit' he was in the habit of devouring the young crocodiles. During our visit this enormous brute was asleep on the bank of his dwelling-place, and seemed quite indifferent to our presence, although we came within a foot of him, and even attempted to arouse him by rubbing his nose with a leg of goat's flesh, which, however, a young one greedily seized. Our attendant tried in vain to excite their ferocity, but beyond a feeble attempt to snap their trenchant teeth, the animals showed no disposition to attack us.

"A pony was wading about in the pond and feeding on the grassy hillocks, but the crocodiles took no notice of him.

"The crocodiles dig deep in the sand, under the neighbouring date-trees, and there deposit their eggs. Quantities of deciduous teeth, of various sizes, were strewn along the slimy sides of the pond.

"Strangers are expected to stand treat, not only by the fakirs and natives, who gain a livelihood by hanging about the pond and showing the monsters, but even the crocodiles themselves seem to anticipate a feast, and on the arrival of a party come out in unusual numbers. Accordingly, we had a goat slaughtered, during which operation the brutes seemed to rouse themselves, as if preparing for a rush. Then our guide, taking piece after piece of the flesh, dashed it on the bank, uttering a low growling sound, at which the whole tank became in motion, and crocodiles, of whose existence we had been before ignorant, splashed through the shallow water, struggling which would seize the prize. The shore was literally covered with scaly monsters, snapping their jaws at one another."

Sir J. Emerson Tennent^[141] has had many opportunities of studying the habits of the Marsh Crocodile. According to him it is essentially cowardly in its instincts, and hastens to conceal itself on the approach of man. One of these creatures, which was overtaken in the jungle by a gentleman riding on horseback, fled to a shallow pool, and thrusting its head into the mud till it covered up its eyes, remained motionless, in profound confidence of perfect concealment.

"There is a popular belief that the crocodile is exceedingly sensitive to tickling, and that it will relax its hold of a man if he can only contrive to reach and rub with his hand the softer parts of its under side. An incident of some reality in this piece of folk-lore came under my own observation. One morning ... we came suddenly upon a crocodile asleep under some bushes of the buffalo-thorn, several hundred yards from the water. The terror of the poor wretch was extreme when it awoke and found itself discovered and completely surrounded. It was a hideous creature, upwards of 10 feet long.... It started to its feet and turned round in a circle, hissing and clanking its bony jaws, with its ugly green eye intently fixed upon us. On being struck with a stick, it lay perfectly quiet and apparently dead. Presently it looked cunningly round, and made a rush towards the water, but on a second blow it lay again motionless and feigning death. We tried to rouse it, but without effect; pulled its tail, slapped its back, struck its hard scales, and teased it in every way, but all in vain; nothing would induce it to move till, accidentally, my son, then a boy of twelve years old, tickled it gently under the arm, and in an instant it drew the limb close to its side and turned to avoid a repetition of the experiment. Again it was touched under the other arm, and the same emotion was exhibited, the great monster twisting about like an infant to avoid being tickled."

In the dry season, when the tanks become exhausted, the Marsh Crocodiles have occasionally been encountered in the jungle, wandering in search of water. During a severe drought, in 1844, they deserted a tank near Kornegalle, and traversed the town during the night, on their way to another reservoir in the suburb; two or three fell into the wells; others, in their trepidation, laid eggs in the street, and some were found entangled in garden fences and killed.

Generally, however, during the extreme drought, when unable to procure their ordinary food from the drying up of the watercourses, they bury themselves in the mud and remain in a state of torpor till released by the recurrence of rains.

C. porosus s. biporcatus.–The premaxillo-maxillary suture on the palate does not form a transverse line, but is W-shaped, and extends backwards as in the rest of the species of Crocodiles to be described. This Indian species is easily recognised by the prominent longitudinal ridge which extends in front of each eye, over the prefrontal bones, and by the absence of sub-occipital scutes. The nuchal scutes consist of four large ones, which form a square, and one or two smaller scutes on each side. The dorsal shield contains four to eight principal longitudinal rows. The digits, webs, and the serrated fringe of the legs are like those of C. palustris. The head and snout, however, are distinctly longer, and more slender in proportion, and the adult has only four teeth in each premaxilla. The general colour is dark olive-brown. Young specimens, as usual, are much paler and are spotted with black.

This species attains a much larger size than the Marsh Crocodile. Specimens of 15 to 20 feet in length are not uncommon, and there is a record of one monster of 33 feet. Consequently this is, both in bulk and length, undoubtedly the largest species of recent reptiles. It is essentially an inhabitant of tidal waters or estuaries, frequently entering salt water and going out to sea. Herewith corresponds its wide distribution, namely, the whole coast of the Gulf of Bengal, extending to Southern China, and across the Malay Archipelago to the northern coasts of Australia. Eastwards it ranges to the Solomon Islands and even to Fiji. Curiously enough, it does not seem to occur on the west coast of India.

According to Tennent it is ready to assail man when pressed by hunger, and the same authority mentions the following serio-comic incident. A man was fishing, seated on the branch of a tree overhanging the water, and to shelter himself from the drizzling rain he covered his head and shoulders with a bag folded into a shape common with the natives. While in this attitude, a leopard sprang upon him from the jungle, but missing its aim, seized the bag and not the man, and fell with it into the river. Here a crocodile, which had been eyeing the angler in despair, seized the leopard as it fell, and sank with it to the bottom.

I have had some personal experience in the bringing up of the young of this species. Two dozen of them had come from Ceylon when quite young, only one foot long. At first they were very shy, and huddled together in their tank, but they took food greedily–strips of fish and, later on, sheep's heart. When frightened they emitted peculiar, high-pitched, half-croaking sounds. Some of them snapped at the finger when touched; others were of a more gentle disposition; the shy ones were undoubtedly the most vicious. Within one year they grew to 18 or 20 inches, and added much to their bulk. Then they were transferred to a deeper and larger tank in a greenhouse, in which they could roam about at liberty. In the daytime they dozed on the margins of their pond, mostly in such a position that, at the slightest alarm, they could plunge back into the water. The strongest specimen left the tank entirely, and took up its favourite place for basking on the stump of a tree, to reach which it had to climb up a rough wall of stones. After three years, several had grown to the length of three and a half, and even four feet, and had by this time become formidable pets. Although handled frequently, they never became tame, the only change in their behaviour being that, instead of rushing off in a fright, and hiding for half an hour at the bottom of the tank, they became more vicious and confident, making for and snapping at the hand which fed them. The nights were spent regularly in the water, either floating with just the nostrils exposed, or in search of food, frogs being their favourite prey, while their main sustenance consisted of "lights," with an occasional mouse, or a piece of solid meat by way of an entrée. Small pieces were bolted. The tough "lights," namely lungs with the windpipe and blood-vessels, were causes of great quarrels. Two or three would get hold of a lump of this kind, tearing at it, and twisting and rolling over in opposite directions. The supply of warm water came through a stout pipe of red india-rubber, and this was an irresistible attraction to the crocodiles. On many a morning the tube was found twisted into a knot, one of the creatures having spent hours in chewing it and in trying to wrench it off. In order to aid digestion they swallowed pebbles. The most favourable temperature of the water was 85° F.; if below 75° F. they refused to eat, but a continued exposure to 60° F. did not hurt them. When the temperature rose above 95° F. they left the water, although means had to be taken to prevent them from lying on the hot-water pipes.

C. niloticus s. vulgaris.–The premaxillo-maxillary suture on the palate is W-shaped. The nasal bones form only a small part of the posterior border of the nasal groove. There are eighteen or nineteen upper and fifteen lower teeth on each side. In old specimens some of the anterior mandibular teeth perforate the premaxillae, as indicated in Fig. 109, and they even pierce through the integument so as to be visible from above. The nuchals are composed of four large scutes, with a smaller one on each side and sometimes one behind, and there is a row of smaller pieces across the occiput. The dorsal shield contains six to eight principal longitudinal rows. The fingers are webbed at the base; the outer toes are very broadly webbed; and there is a serrated fringe on the outer side of the leg. The general colour of the adult is dark olive-brown; the young are paler, with black spots and vermiculations. The under parts are yellowish white.

The Nile Crocodile is essentially African, ranging from the Senegal to the Cape and to Egypt. It is also very common in Madagascar. Nothing is known about its occurrence in Arabia, but a few specimens of rather small size seem still to exist in Syria, in the Wadi Zerka, an eastern tributary of the Jordan.

Even in historical times the Crocodile must have been very common in lower Egypt, to judge from the number of mummies preserved by the old Egyptians. Now it is practically exterminated, and there are scarcely any left below Wadi Halfa.

Such a conspicuous and dangerous creature has naturally always enjoyed notoriety. It is well described in one of the oldest writings of the world, the Book of Job. "Canst thou draw out leviathan with an hook? or his tongue with a cord which thou lettest down?... His scales are his pride, shut up together as with a close seal. One is so near to another, that no air can come between them. They are joined one to another, they stick together, that they cannot be sundered.... Lay thine hand upon him, remember the battle, do no more." Bows and arrows, spears and clubs, are of little avail against such a monster; the dragging out of a hooked, full-grown specimen requires many men and is a formidable task. Of course firearms have changed all this, and its invulnerability to bullets is nonsense. It is true that a bullet sent into the head is generally ineffective, since it is a hundred to one that the bullet does not hit the small brain, and even if it does, the creature sinks to the bottom and is lost to view until decomposition sets in and the gases developing in the body cause it to float.

Herodotus has quaint stories about these crocodiles and their worship. Amongst other stories he mentions that the bird Trochilus, supposed to be the Pluvianus aegyptius, a kind of Plover, slips into the gaping mouth to pick off the leeches which infest the reptile's gums. "In Egypt it is called Champsa, but the Ionians call them κοκοδρίλοι on account of the resemblance to the lizards which live on their garden walls." This is in fact the origin of the name crocodile, κόρδυλος being the ancient Greek for lizard and newt. With reduplication κορκόρδυλος and by metathesis ultimately κροκόδειλος. The Arabic name is ledschun.

The story about the Plover seems to be true. These birds are sometimes seen sitting upon basking crocodiles, and since the latter are in the habit of resting, perhaps half asleep, with the mouth wide open, it is possible that these agile birds do pick their teeth, and that they, being also very watchful, by their own cry of warning and by fluttering off on the approach of danger, give the alarm to the crocodiles and thus benefit them in more than one way.

But the equally old story about the Ichneumon or Mongoose is an idle invention. Mongooses are partial to eggs, but they certainly prefer those of hens and other birds to those of the crocodile, which are far too hard and strong to be broken by such a little animal. Moreover, as we shall see presently, the eggs are far too well concealed.

The best account of the habits of these crocodiles is the one given recently by Voeltzkow,^[142] who has spent a long time in Madagascar to collect material for the study of their development.

He says that C. niloticus is not only the most common reptile, but perhaps the most common vertebrate in Madagascar. It occurs in every pool and river in great numbers, especially upon the sandbanks of the Betsiboka River, where one may see more than one hundred within one hour's paddling down stream. The largest specimen measured by Voeltzkow was 13 feet long; the largest in the National Collection is a little less than 15 feet.

The crocodiles are caught in various ways. The simplest apparatus consists of two pointed sticks, which are fastened cross-wise within the bait to which is attached a rope, and this is made fast on the bank of the river or lake. The animal, when it has once swallowed this spiked bait, keeps its jaws firmly closed, so that it can be dragged out of the water. Another method is more reliable. A long and strong rope is made into an easily slipping noose, with an opening of about 18 inches. The bait is attached to the upper part of the noose, while the lower portion is kept open by a springy branch, the whole thing being so balanced that it will float upright. When a crocodile seizes the bait, which it does with a side jerk of the head, the branch falls out of the noose and the latter closes around the upper or lower jaw.

These crocodiles dig long subterranean passages of 30 to 40 feet in length; the passage opens in the bank below the level of the water, and gradually ascending ends in a somewhat wider compartment, which allows the creature to turn round. Two or three air-holes are pierced through the ceiling of the burrow, in which bones and other remains of food are often found, so that the natives' belief, that the crocodiles retire into these chambers in order to devour their prey in undisturbed secrecy, appears very probable. When suddenly disturbed or frightened they take to these lairs, and since their position is clearly marked by the air-holes, the natives block the passage and then dig the animal out from above.

Eggs are laid, in Madagascar, from the end of August to the end of September; the number of one set varies from twenty to thirty. They are deposited in a nest. This is in the ground, mostly in white sand, and consists of a hollow 18 inches to 2 feet deep. The walls are rather vertical, but near the bottom they are undermined, and here the eggs are placed. The centre of the pit being somewhat higher, the eggs roll by themselves into the undermined peripheral region. The laying takes place during the night, mostly a little before daybreak. After one half of the eggs has been laid, they are covered up with sand, whereupon the other half is deposited. Then the hole is completely filled up and no visible traces are left behind; but the mother sleeps upon the nest and thus leads to its discovery. The position of the nest is so chosen that it cannot be reached by moisture from below; the eggs are most susceptible to moisture, a very slight amount of which causes them to turn bad.

The shape of the eggs of one and the same clutch varies much, some being elliptical, others cylindrical with rounded off ends. Their size varies from 5.5 to 9 cm. in length, and 4 to 5 cm. in width. The shell is white and glossy, thick and hard, either roughly granular or smooth. They are hatched in about twelve weeks.

Voeltzkow feels certain that the mother returns to the nest at the proper time in order to dig the young ones out and to conduct them to the water. To test this story he had a nest surrounded with a fence; the mother returned several times and partly destroyed the fence, which was then replaced by a stronger one. One day, when the young had been hatched, the nest was found to be filled with sand, the shells and one dead little crocodile being at the bottom of the hole. The mother had dug a deep ditch below the fence, but had not succeeded in reaching the nest, although she had received and conducted her offspring away. As a rule, when the young are hatched, the sand and the shells are found to be scraped out of the nest. The mother is probably warned by the hiccough-like sound which the young emit while still within the unbroken shell. Voeltzkow heard them piping from the other end of his room, the eggs being covered with a layer of sand two feet high. The sounds were heard when he walked past the nest, or knocked against the box. Possibly the young hear the mother when she retires to the nest to sleep on it, and give her warning to remove the eggs out of the groove. However, they do not break the shell until several days later.

The hatching is not caused by the rainy season, since it took place a fortnight before the first showers. The "egg-tooth" of the newly hatched young is 0.5 to 0.75 mm. high, bicuspid, and acts like a borer or auger. It is still visible on the tip of the upper jaw, in front of the nose, when the creature is two weeks old. The newly hatched crocodile is of an astonishing size, so that it is rather puzzling to understand how it was stowed away in the egg. For instance, an egg of 8 cm. length and 5 cm. width, sends forth a crocodile 28 cm. or 11 inches in length. Even at this early age they snap at the finger.

The egg is covered by a hard shell, within which is a thicker outer and a thinner inner membrane. The "white" is jelly-like, sometimes of a greenish tinge, and is so consistent that it will not flow. The yolk is round, and so large that it nearly reaches the shell-membrane in the short diameter. The yolk itself is surrounded by a very thin but strong membrane.

The embryo begins to develop long before the egg is laid. When laid the germ is about 4 mm. long and shows about twelve somites. The cephalic bend begins at the end of the second week, the tail grows longer and the embryo becomes curled up. At the end of the third week it measures 10 mm. in a straight line from brain to vent. The limbs begin to bud in the fourth week. With the sixth week the final shape begins to reveal itself, and is completed at the age of eight weeks; but a third month is necessary to ripen the embryo.

C. cataphractus is the Common Crocodile of West Africa, from the Senegal to the Congo. In opposition to C. niloticus it does not enter brackish water. It is easily recognised by the very slender snout, which rather resembles that of the Gavial; but the mandibular symphysis, although extending to the level of the eighth tooth, does not reach the splenial bones. The premaxillo-maxillary suture on the palate is not transverse, but extends backwards. In conformity with the length of the snout the maxillaries meet in the dorso-medial line behind the nasal opening, thus excluding the nasals from the latter. The nuchal scutes consist of two large pairs, almost in contact with the dorsals, six of which form the principal longitudinal rows. The gular and ventral scutes ossify in the adult, hence the specific name. The fingers and toes are slightly webbed. General colour above, dark olive-brown; yellowish below. The young are olive with large black spots.

The natives of the Lower Congo catch the crocodiles with two pointed sticks tied together cross-wise, surrounded with entrails by way of a bait. The whole is fastened to a pole or a strong rope and thrown into the river; and a narrow line, with a float attached to the cross-sticks, indicates the whereabouts of the crocodile when it has taken the bait and has sunk to the bottom.

C. johnstoni, of Northern Australia and Northern Queensland, and C. intermedius, of the Orinoko, are allied to C. cataphractus, at least so far as the configuration of the bones of the slender and long snout is concerned. The former is small, scarcely reaching the length of 7 feet, while the South American species grows to 13 feet.

C. americanus s. acutus.–This species, which inhabits the West Indian Islands, being there the only representative of the order, occurs also in Florida, and extends through the warmer parts of Central America into Venezuela, Colombia, and Ecuador. Its characteristic feature is a median ridge or swelling on the snout. The length and relative width of the latter varies considerably. The maxillaries sometimes meet dorsally, or they remain separated by the narrow nasals, which in this case reach the posterior corner of the nasal groove. The nuchal scutes vary likewise; there being often a smaller pair on the side of and another behind the four principal scutes, which, as usual, form a square. A transverse row of little suboccipital scutes is also common. Largest size about 12 feet long.