Rhinoderma.–Omosternum and precoracoids present. Palate without teeth. Tympanum indistinct. Terminal phalanges simple, and not dilated. Tongue heart-shaped, and free behind. Pupil horizontal. Habitat, Chili.

Rh. darwini, the only species, was discovered by Darwin, during the voyage of the Beagle. Its total length is only 3 cm., or little more than one inch. The shape is grotesque, as the skin is prolonged, beyond the very small triangular mouth, into a false nose, i.e. a nose-shaped projection, while the nostrils remain at their original place. The skin is smooth above, granular on the under parts, and forms a triangular flap or spur-shaped appendage on the heel. A glandular fold extends along the sides of the body. The general colour is brown above, black below, with large white patches, the latter colour being sometimes predominant on the throat and chest. The male has a pair of internal vocal sacs, and the use of these as nurseries for the young has made this species famous.

Espada^[99] has given an elaborate account of this species, which lives on the ground in shady woods. Its voice sounds like a little bell, and before taking its short jumps, it erects itself vertically upon the hind-limbs. The gular sac of the male opens by two slits, one on each side of the tongue. Generally this sac does not extend beyond the middle of the chest, but during the breeding time the eggs are put into it, whereupon it becomes greatly distended, so much so indeed that it reaches back as far as the groins; dorsalwards around the flanks, almost to the vertebral diapophyses; ventrally and forwards it reaches the chin. The walls of the sac are of the same structure as the buccal lining, of which they are in fact continuations. They adhere, at intervals, to the cutis and to the pectoral and abdominal muscles.

The effect of the distension of the sac upon neighbouring organs is twofold. First, the viscera are pressed back within the abdomen; this disturbance is temporary and does not apply to all specimens; the feeding in no way impeded. Secondly, a permanent change is produced in the direction of the precoracoid bars, in such a way that each bar is curved tailwards and rests with its ventral half upon the coracoid; owing to this forcible bending the clavicles do not meet each other. There is, of course, not so much space gained by this slight rearrangement of the shoulder-girdle as Espada implies, but we have here, perhaps, an illustration of direct correlation between two originally independent organs, namely, shoulder-girdle and vocal sacs. Repeated distension of the throat-bag during every breeding season, while the whole organisation of the male is in a highly excitable condition, has pressed the clavicular bars back, or rather has staved them in, and this at first pathological and abnormal condition has at last become a fixed feature. It is to be regretted that we know next to nothing about the habits, especially the mode of breeding, of the other genera which likewise have reflected or very feeble precoracoids and clavicles. Their weakness or even complete absence must have a reason, or rather must have had a cause.

The pairing and oviposition, and the manner in which the eggs are conveyed into the gular sac, have not yet been observed. Espada examined five males with young, the number of which varied from five to fifteen. In one male with eleven embryos the most developed tadpoles measured 13.5 mm. from the snout to the end of the tail, and they were lying within the chest of the father, the less advanced in the farther recesses of the bag. Three of the tadpoles had already completely-formed fore- and hind-limbs, while the arms were still hidden. The least developed were still globular, a proof that the eggs are conveyed into the bag. Another male with fifteen embryos looked as if it had gorged itself with the almost fully-formed tadpoles, which measured 14 mm. They were quite irregularly distributed, and nowhere attached to the walls of the bag. None of them had horny jaw-armaments, and not even the smallest specimens showed any traces of gills, resembling in this latter character those in the female brood-pouch of Nototrema. The intestine of the tadpoles is short and thick, coiled up spirally and filled with yolk, certainly not with vegetable or other foreign matter. Consequently the entire development from the egg to the complete stump-tailed little creature is undergone within the pouch; and this, after the young have escaped, probably shrinks back to its original size and acts as a gular vocal sac.

Phryniscus.–About ten species of this tropical American genus are known; they extend from Costa Rica to Buenos Aires. They differ not inconsiderably in various details. The tongue is elliptical, entire, and free behind. The palate is smooth. The tympanic disc is absent. Fingers and toes more or less webbed, sometimes with swollen tips, without, however, forming adhesive discs. In a few species the first toe is quite indistinct. The male has a subgular vocal sac. The mouth is small, and there is a short snout. The general appearance varies much. Ph. nigricans of Uruguay, etc., is stout and has very short hind-limbs; the skin of the upper parts is black, spotted with white, and covered with warts. Most of the other species are slender, with larger hind-limbs and a perfectly smooth skin, the coloration of which ranges from dull uniform brown, or black with crimson markings, to bright green with purple spots. The under parts are, as a rule, conspicuously coloured, a rare feature in Anura, the favourite colours being orange, yellow, or even crimson, with or without black patches.

Phryniscus nigricans has been observed in Paraguay by Budgett,^[100] who gives the following account. This is a brilliantly coloured frog of toad-like appearance, and about 33 mm. in length. The ground-colour is black, with yellow spots or patches on the upper parts, the under parts are black, with scarlet blotches, the palms of the hands and soles of the feet are scarlet. At the breeding season both sexes utter a call-note which consists of two clear musical "rings," followed by a long descending "trill," like that of our British Greenfinch. This frog, which at ordinary times is the slowest and boldest of frogs, is now active and excessively shy. Swimming rapidly between the blades of grass, it climbs a tuft, and dilating its throat, repeats its call; but if in the least disturbed, it is suddenly gone. The eggs are laid in quite temporary pools in grassy ground, and form separate globules of jelly, which float on the surface of the water, and are heavily pigmented. The development is excessively rapid. The segmentation beginning at 10 A.M., they were hatched and wriggling about by 7 A.M. the following day. They are probably washed down into deeper pools by the retreating waters, and for this purpose the manner in which the eggs are laid, namely, in separate globules of jelly, seems especially suited.

Brachycephalus ephippium in Brazil, the only species, is remarkable for the development of a broad dorsal shield of bone, which is fused with the processes of the second to seventh vertebrae, an ossification which strongly resembles that of several species of the likewise Brazilian Ceratophrys, a genus of the Cystignathinae.

Stereocyclops is remarkable for the peculiar formation and protection of the eyeballs. The anterior portion of the sclerotic is ossified into a ring, which surrounds the transparent cornea. Another peculiarity lies in the metasternum, which is so much broadened out that its cartilage is in wide contact with the posterior edge of the coracoids. The epidermis is everywhere "thickened by a chitin-like deposit." The only species, S. incrassatus, found near Rio Janeiro, is an altogether aberrant creature. Its general appearance recalls that of Pipa. The gape is large, with a slightly projecting muzzle; the limbs are so short that the upper arms and the thighs scarcely stand out from the broadened and flattened body, which is leathery brown, with a narrow white median line extending dorsally from the nose to the vent.

Engystoma, with about five species in the Southern States, Central and South America, is the type-genus of the whole family, chiefly on account of priority of name. It is fairly characteristic in so far as the mouth forms a narrow, somewhat projecting snout; the precoracoids, the clavicles, and the omosternum are absent, the palate is devoid of teeth, the lining of the mouth forms a dermal ridge across the palate and another in front of the oesophagus, the tympanum is hidden, the sacral diapophyses are moderately dilated, and the tongue is elliptical and free behind. The pupil is vertical. The fingers and toes are free, ending in slightly dilated or blunt tips; the terminal phalanges are simple and the hind-limbs are short. The male has a subgular vocal sac.

The most northern species is E. carolinense, living in the Southern United States, concealed under the bark of fallen trees or in old fences. The skin is smooth, but forms a fold across the head, behind the eyes. The general colour is brown, with light, whitish dots on the under parts. Total length 1 inch.

Breviceps is a South African genus with three species. The coracoids are very strong and directed backwards, but so broadened that they form a long and strong symphysis, touching in front that of the precoracoids, which stand transversely and are well developed. The metasternum is cartilaginous and decidedly small. The sacral vertebra has much dilated diapophyses and is co-ossified with the coccyx. The general appearance is extremely stout and short, the head being almost drawn into the nearly globular body, and ending in a short snout with a small mouth-opening. The tongue is long and oval, not nicked, but slightly free behind. B. mossambicus is about 2 inches long, and looks like an overstuffed round bag, out of which the short arms and legs project from the elbows and knee-joints only. The tarsus is provided with a strong horny, spade-like tubercle, which enables the creature to dig into the ground, and into the nests of termites, which seem to be its chief food. Peters found this species in enormous numbers, during the tropical rains, coming out of the ground, whither they withdraw again completely for the dry season. The skin is smooth, reddish brown above, with darker patches; the under parts are dull white, with a large black patch on the throat.

Hemisus is another African genus, with two species, H. guttatum in Natal, and H. sudanense in East and West Africa. This genus is so exceptional in its shoulder-girdle, that Cope separated it from all the other Anura as a special sub-order Gastrechmia. The precoracoids are extremely strong, and form a broad symphysis from which springs the long cartilaginous omosternum; the coracoids are slender, very long, and converge backwards to a narrow symphysis, and there is no metasternum. The two symphyses are connected by a narrow cartilaginous median bar, probably produced by the much modified epicoracoid cartilages. However, except for the reverse development shown by the omo- and meta-sternum, it is easy to connect this apparently quite anomalous shoulder-girdle of Hemisus with that of Breviceps. (cf. Fig. 5, 5 and 6, p. 25). The sacral diapophyses are slightly dilated; the fingers and toes are free and end in points. The tongue is triangular, broader in front. The lining of the mouth forms a transverse ridge across the palate, and another in front of the oesophagus. The male has a subgular sac. The general shape is stout, the head small and ending in a pointed snout. Colour brown above, with whitish spots. Total length about 2 inches.

Glyphoglossus has a peculiar tongue. It is elongated, notched behind and in front, divided into two lateral halves by a deep groove; moreover, the tongue is not only extensively free behind, but also slightly so in front. The skin of the palate forms a transverse serrated ridge. The precoracoids and the omosternum are absent; the metasternum is a well-developed cartilaginous plate. The sacral diapophyses are moderately dilated; the terminal phalanges are simple. G. molossus, the only species, is olive-brown above, marbled on the sides; the under parts are uniformly whitish. This creature, about 2 inches in length, looks like a roundish bag, with a ridiculous, short face. The type-specimen, still the only one known, was taken by Dr Theobald under the following circumstances:–"I had halted one day within the tidal portion of the Irawaddy delta, to enable my boatmen to prepare their dinner. One of my servants, having cooked his rice, poured out the hot water as usual on the ground, and some of it went down a hole that happened to be near the spot. No sooner, however, had the hot water disappeared than out scrambled in great haste a fine Glyphoglossus, only, alas! to be transferred to a collecting jar."

Phrynella.–The tongue is heart-shaped, free behind. The palate is smooth and toothless. The fingers and toes end in small discs, supported by T-shaped phalanges; the fingers are free, the toes extensively webbed. Precoracoids absent; metasternum cartilaginous. Pupil horizontal. Malay Peninsula.

Ph. pollicaris is dark olive brown above; an oblique yellow line runs from the eye to the angle of the mouth; a pale yellow mark, across the forehead, through the eyes, and down the sides of the body. A dark-centred yellow patch on the anal region. The limbs are banded yellow and brown. The under parts are brown, with paler specks, dark on the throat. Iris red brown. The whole coloration changes considerably.

"They inhabit the hills of Perak from 3000 feet upwards, and live in holes in trees, which are so situated as to contain more or less rain-water. They have a loud flute-like, musical note, which they utter at irregular intervals, principally during the night. The form and size of the hole in which they are seem to have a great deal to do with the loudness of the note, as specimens when extracted from their holes have far more feeble vocal powers than they had when in them. These frogs blow themselves out with air, and look more like bladders than anything else. When inflated they float on the surface of the water, and will remain motionless for a long time, with legs and arms stretched out."^[101]

Callula.–The tongue is round, entire, and free behind. The palatine bones form an acute, sometimes toothed ridge across the palate; two dermal serrated ridges in front of the oesophagus. Fingers free, sometimes with dilated tips, supported by T-shaped phalanges. Precoracoids and omosternum absent; metasternum cartilaginous. Pupil round. About seven species in the Indian region.

C. pulchra.–The following account has been extracted from Mr. S. S. Flower's observations:^[102]–

This pretty creature inhabits most of the warm portions of the continental Indian region, from India and Ceylon to South China and Malacca. The back is a rich dark brown, divided from the yellow of the head by a narrow black line which extends from eye to eye and forwards to each nostril. A conspicuous yellow band runs from the eyes to the hind-limbs. The sides of the body and the limbs are mottled yellow and brown. The under parts are dirty buff; the throat of the male is black. The intensity of colouring varies individually and from time to time, the contrast between the brown and yellow being occasionally very brilliant. Total length up to 3 inches, the male being the smaller sex.

"I have been told by both English and natives that this frog was unknown in Singapore until some nine or ten years ago, when it was introduced by a half-caste (why, it is not known), and that it rapidly spread about the island. It is now well known as the 'Bullfrog' by the English in Singapore, and detested for the noise it makes at night. The voice of these rotund animals can be heard every night after heavy rain; it is a deep guttural croak, 'wau-auhhhh,' very strident and prolonged. The males croak while floating on the surface of the water, the single vocal sac under the mouth inflated like a globe, and the arms and legs extended. They can hop well on land and are good swimmers. The skin is excessively slimy; the secretion comes off profusely, and dries on the hand into a sort of white gum, with a faint aromatic smell. This gum dissolves in hot water and coagulates in cold. The general appearance of these frogs is very stout, their girth being about twice the length from snout to vent. The tongue, which is oblong in spirit specimens, in life is very elastic, assuming, when extended, a vermiform shape and reaching about 4 cm. in length. They appear after sunset, crawling on old wood and feeding on white ants."

Sub-Fam. 2. Dyscophinae.–With teeth in the upper jaw.

This small group of nine genera, with scarcely more than one dozen species, all with one exception living in Madagascar, has been separated by Boulenger from the Engystomatinae merely on account of the presence of teeth on the upper jaw and on the vomerine margin of the palatine bones. He himself remarks that Calluella may be considered a toothed Hypopachus, and Plethodontohyla a toothed Callula. These are obvious cases of convergent analogy. Except for the teeth, the Indian Calluella would be merged into the American Hypopachus, and this would present an instance of the most puzzling geographical distribution. In the case of the other two genera, one Indian and Malayan, the other Malagasy, no such suspicion would arise, since there are many other instances of such a coincidence of distribution. There is the same divergence or unsettled condition in the modification of various parts in the Dyscophinae as in the Engystomatinae. The precoracoid bars are weak and curved backwards, and closely pressed against the strong coracoids, in Dyscophus, Calluella and Platypelis, while these elements are reduced to unossified bars, and the clavicular portions completely lost, in Plethodontohyla and in Phrynocara. The omosternum is absent and the metasternum is small in all except Dyscophus, in which both these parts are exceptionally well developed and large, although remaining unossified. The palate of Dyscophus and Calluella is provided with curious, serrated dermal folds like those which are so common in the Engystomatinae; and well-developed discs on the fingers and toes, supported by T-shaped phalanges, are possessed by Platypelis, Cophyla and others. The sacral diapophyses are dilated. The pupil is either horizontal or vertical. Those which are provided with discs to the fingers and toes are climbers, and mostly slender and long-legged, sometimes of very small size, for instance Cophyla, the body of which is scarcely one inch in length.

The genera can be determined by means of the following key:–^[103]

Dyscophus antongili.–Madagascar. General appearance stout, with short legs and a wide mouth. Total length about 3 inches. The skin is mostly smooth, and forms a broad glandular fold which extends from the eye to the groin. The upper parts are beautiful magenta red, with a purplish streak beneath the lateral folds; the under parts are yellowish white, with minute grey specks. Red or pink colours, and the lateral folds, occur also in most of the other members of this family, for instance in the Indian genus Calluella.

Sub-Fam. 3. Genyophryninae.–With very small teeth on the anterior portion of the lower jaw.

Genyophryne thomsoni.–Pupil horizontal. Tongue oblong and entire. With teeth on the palatine bones, and a serrated transverse dermal ridge in front of the oesophagus. Sternum cartilaginous. Precoracoids absent. Sacral diapophyses moderately dilated. Tympanum hidden. Head large and much depressed. Heel with a triangular dermal flap. The smooth skin is pink brown above, with blackish marks; a light line extends on each side from the eye along the back. Under parts black. About 32 mm. in length. Sudest Island, between New Guinea and the Louisiade Archipelago.

Fam. 7. Ranidae.–Frogs, in the true sense, are all well diagnosed as Firmisternia, with cylindrical sacral diapophyses. According to the presence or absence of teeth in the jaws they can be subdivided as follows:–

Sub-Fam. 1. Ceratobatrachinae, with teeth in the upper and in the lower jaws. The sole representative is the genus Ceratobatrachus.

Sub-Fam. 2. Raninae, with teeth in the upper, but none in the lower jaw. These are the Ranidae of Boulenger in the Catalogue of Batrachia Salientia.

Sub-Fam. 3. Dendrobatinae, without teeth in the upper and lower jaws.

Sub-Fam. 1. Ceratobatrachinae.–Teeth present in both jaws. Those of the lower jaw, between 20 and 30 in number in Ceratobatrachus, the only genus, are nearly all inserted upon the articular bone; only 2 or 3 are carried by the dentary element, which, although large, enters into the formation of the upper border of the jaw at the anterior end only. In the small extent of the share of the dentary in the formation of the edge of the lower jaw, and in its anterior "toothlike" process, Rana adspersa of Africa bears unmistakable resemblance to this genus. The tongue is deeply notched, and free behind. Pupil horizontal. Vomers furnished with teeth. Tympanum distinct and large. Precoracoids present. Omosternum and presternum with a bony style. Sacral diapophyses cylindrical. Fingers and toes free, with swollen tips. Outer metatarsals united. Male with two internal vocal sacs.

G. guentheri, Solomon Islands, the only species, has an enormous mouth and a triangular head not much smaller than the rest of the body. The skull is furnished with prominent ridges and a small curved spine at the angle of the jaws. The hind-limbs are rather short. The skin of the upper parts shows linear ridges, variously arranged; that of the belly is granular. A triangular dermal flap on the tip of the muzzle, one on the upper edge of the eyelids, others on the heel and above the vent. The colour and markings are very variable, the ground-colour is yellowish to pink, brown, grey or olive, with darker and lighter markings. Total length of the males 3 inches, of females 3½ inches.–Guppy, the discoverer of this peculiar creature, remarks that "horned Frogs are very numerous in these islands, and so closely do they imitate their surroundings in colour and pattern, that on one occasion I captured one by accidentally placing my hand on it when clasping a tree."

Sub-Fam. 2. Raninae.–The vertebrae are procoelous and devoid of ribs. The precoracoids are always present and ossified from the clavicles, and are parallel with the much stronger and ossified coracoids. The omosternum usually possesses a bony style, but in the Indian genera Nannobatrachus and Nannophrys and in Phyllodromus of Ecuador it remains cartilaginous, and in Colosthetus of Colombia it is absent. The metasternum also possesses a bony style, but it remains cartilaginous in the Indian genera Oxyglossus, Nannophrys, Nannobatrachus and Phyllodromus, in the last two genera rather reduced and slender, while in the Ecuadorian and Colombian genera Hylixalus, Prostherapis and Colosthetus, it is reduced to a membranous piece. In quite a number of genera the normal number of phalanges is increased by one owing to the intercalation of an extra phalanx between the terminal and the otherwise penultimate phalanx.^[104] This is the case in all the species of Cassina, Hylambates, Rappia, Megalixalus, Rhacophorus, Chiromantis, Ixalus and Nyctixalus, but it is doubtful if all these genera are thereby more nearly related to each other than to the rest of the Raninae. The structure of the tips of the fingers and toes exhibits more variety. The terminal phalanges are mostly simple, with slight swellings at the ends, or they are Y- or T-shaped in conformity with more or less developed adhesive discs; in the African genus Hylambates only they are claw-shaped, as in the Hylidae.

Gampsosteonyx batesi, recently described by Boulenger from the Gaboon, shows a unique modification of the terminal phalanges of the second to the fifth toes. They are transformed into sharp and curved claws, like those of a cat, but instead of horny sheaths, it is the bone itself which is thus sharpened and perforates the skin, an anomaly reminding us of the ribs of Triton waltli. Total length of the type-specimens, about 3 inches.

Adhesive discs are common, and are best developed in Rhacophorus, Ixalus, Rappia, and Megalixalus. In the Neotropical genera, excepting Colosthetus, the discs are very peculiar, being provided on the upper side with leathery scales which are separated by a fissure. The fourth and fifth metatarsals either diverge and are connected by a distinct web, or they lie close together with only a groove between them, or lastly they appear externally united.

The tympanic disc is very variable, large, small or quite hidden. Vomerine teeth are present or absent. The pupil contracts into a horizontal slit except in some Palaeotropical genera. The tongue is universally free behind, mostly deeply notched, and can be well protruded; only in the Indian Oxyglossus and in the Neotropical genera, excepting Hylixalus, its posterior margin is entire.–There are terrestrial, arboreal, and aquatic members in this large sub-family. The geographical distribution of the Raninae, which comprise about twenty genera with at least some 270 species, is almost entirely Arctogaean. None, with the exception of three species in the Papuan subregion, occur in the Australian region; and only four genera, with one or two species each, inhabit the tropical Andesian district, the remainder of South America being without any Raninae. All the species of the whole Periarctic region belong to the genus Rana except in Eastern Asia, where the closely allied genus Rhacophorus occurs also. The entire sub-family of Raninae is, in its fulness and diversity of development, essentially Palaeotropical.

Many of the genera, even in the present more liberal sense as interpreted by Boulenger, are based upon unimportant characters, and in reality run into each other. This is for instance the case with Rana and Rhacophorus.

The following tabular arrangement is merely a key for determination and does not necessarily express relationships. The presence or absence of vomerine teeth is a character easily ascertained, but it separates closely allied genera, for instance, Rhacophorus from Ixalus and Micrixalus from Rana.

The genera with extra, interpolated phalanges are marked *.

Key for the Determination of the genera of Raninae.

Phyllobates.^[105]–This is one of the few Neotropical genera, and like nearly all of these has peculiar adhesive discs on the fingers and toes, each disc bearing on its upper surface two dermal scales. The tympanum is distinct. Vomerine teeth are absent. The general appearance of the five species is that of tree-frogs. One species, Ph. bicolor, yellowish above, dark brown beneath, lives in Cuba. The others inhabit Central America and Venezuela. They seem to have peculiar nursing habits. Ph. trinitatis of Venezuela and Trinidad carries its tadpoles on its back, on to which the young fix themselves by means of their suckers. Nothing is known about their breeding habits, for instance whether the young are hatched on the back, or, as seems more likely, if the parents (the specimen described by Boulenger^[106] is a male) only give their offspring a temporary lift in order to convey them from a drying-up pool to a healthier place. It is remarkable that several species of Dendrobatinae, which inhabit the same countries, have precisely the same habits.^[107]

Arthroleptis.–Slender and long-limbed little frogs, about one inch in length. The fingers and toes are free, very slender, and end in slightly dilated tips, the supporting phalanges being simple. The tympanum is variable. The skin is smooth or finely granulated. The colours are inconspicuous, brown or grey tones usually prevailing. About ten species are known, mostly from Continental Africa, a few from Madagascar and the islands in the Indian Ocean.

A. seychellensis.–Brauer^[108] has discovered the mode of nursing of this frog. He found a specimen of A. seychellensis which carried nine tadpoles on its back, in the month of August, in the Seychelles, about 1500 feet above sea-level, upon an old tree-fern. The little ones were already provided with long tails, the hind-limbs were partly free, the fore-limbs still covered by the skin, and they held on by their bellies; not, like the young of Phyllobates, by their "suckers." Another specimen carried young which were still further developed. He also found an old frog, near which was lying a little heap of eggs, not enveloped in a common mass of jelly. The old frog escaped, but the eggs were taken care of in a vessel with moist sand at the bottom. By the following morning the eggs were hatched and the tadpoles were clinging by their bellies on to the walls of the glass. Brauer concludes that the young, when hatched, creep on to the parent's back, he or she waiting near the heap of eggs until the latter are ready. Curiously enough, he did not find out the sex of the nurse, nor are we told if the young are taken to the nearest water to finish their metamorphosis, or if they remain upon the parent's back until they hop off as baby-frogs. The yolk is very large. When the four limbs are already developed, the gill-cavity possesses no gills and no outer opening; and since the lungs are only just beginning to sprout, the tadpole must needs breathe by means of its skin. The jaws have no horny coverings. The adults live on the ground between moist leaves, and eat chiefly termites.

Cornufer, with about twelve species, is an essentially Austro-Malayan and Polynesian genus, but one species, C. johnstoni, has been found in the Cameroons. The fingers and toes are free, and their T-shaped phalanges support adhesive discs. The tympanum is distinct. The general shape is frog-like, usually with slender and very long hind-limbs and toes, the discs of the latter being much smaller than those of the fingers. The coloration is dull, mostly brown, more or less marbled, whitish below. The upper eyelid of some species, e.g. of G. unicolor of New Guinea, has a small tubercle, hence the generic name. The skin of the back is glandular and granular, forming slight folds on the back and on the sides of the head in some species. The male has one or two internal vocal sacs.

C. corrugatus is one of the most widely distributed species, inhabiting the Philippines, New Guinea, and Duke of York Island. The granular skin forms longitudinal folds on the back, one of which reaches from the eye to the shoulder. Brownish above with darker markings, below yellowish, with or without brown spots on the throat.–Three species inhabit the Fiji Islands.

Of C. solomonis of the Solomon Islands little is known about the propagation, although the large size of the egg, which measures 5 mm. in diameter, suggests that the young undergo most or the whole of their metamorphosis within the egg.

Chiromantis is distinguished by the peculiar arrangement of the fingers, the first and second being opposed to the others; their terminal phalanges are obtuse and support small knobs or discs. The general shape is that of a frog with long and slender hind-limbs. The tympanum is distinct.

Ch. xerampelina, the type-species, was discovered by Peters at Mozambique; it is a middle-sized frog, about 2 inches in length, brown above with reddish spots on the sides; the male is devoid of vocal sacs.

Ch. petersi, a native of East Africa, differs from the preceding by the possession of an internal vocal sac. Ch. rufescens = guineensis shows very little of the typical grasping arrangement of the fingers; the two inner ones are separated from the two outer fingers by a wide gap, but they all lie in the same plane, are much webbed and possess large discs, so that by the latter two characters a link is formed with Rhacophorus, to which the present genus is closely allied. Total length about 2½ inches.

Buchholz^[109] has observed the peculiar breeding habits of this rather large, brown, and slender tree-frog in the Cameroons. In the month of June he found on the leaves of a low tree, standing in the water, a white foamy mass, like the froth of a broken egg, containing a number of newly hatched larvae and quite transparent eggs. Within three or four days this mass became fluid, and the larvae, provided with external gills and a long tail, swam about in the slime. In the natural course of events the larvae are probably washed down into the water by the rain. He found that the female deposits the eggs in the foamy mass at night, during the months of June and July, on various kinds of trees, either between the roots or in a cavity formed by gluing together several leaves, sometimes 10 feet and more above the water, or near the margin. On one occasion the mother was seen sitting upon the foamy mass, clasping the same with its four limbs.

Rhacophorus.–This large genus, containing more than forty species, has a curious distribution. At least one dozen species are found in Madagascar, eight or nine in Ceylon, the rest in Southern India, the Himalayas, the Malay Islands and Philippines, extending northwards through China and Southern Japan. Therefore this genus, with the three species of the African Chiromantis, extends over the whole of the Palaeotropical region. The generic name has reference to the possession by many species of little dermal flaps, especially at the inner side of the heel, and it has nothing to do with the parachute-like use of the hands and feet of certain species, to be mentioned presently.

The terminal phalanges are generally bifurcated, rarely obtuse, and support well-developed adhesive discs. The fingers and toes are webbed to a variable extent. The two outer metatarsals are likewise connected by a web. The tympanum is distinct. The general appearance is that of tree-frogs, and many of them are green. The males have one or two internal vocal sacs. Not all the species have dermal appendages. Rh. maximus, for instance, the largest of all, living in the Himalayan forests, has none. A heel-flap occurs in some half-dozen Indian species; and Rh. madagascariensis has these flaps on the heels and on the elbows. Some have queer little lappets above the vent, or on the edges of the arms and legs; in others the bend of the arm is fringed. The small size of these appendages, in comparison with the webs and discs, makes them practically useless so far as increase of surface is concerned, and they have most likely some other, although unknown meaning, especially the flaps over the vent. Lastly, in the majority of species the fingers are not more than half-webbed, or even less, and in a few only, the webs reach down to the discs.