The sole representative of this genus is the Tibetan Water-Shrew (N. elegans, Fig. 288), which differs from all other members of the family by the webbed toes and the presence of the disc-like adhesive pads on the under surface of the feet, which are believed to enable the creature to hold on to smooth rocks or stones in the beds of the streams it inhabits. This species is probably more completely aquatic in its habits than the allied Chimarrogale.

Fossil Soricidæ.—Remains of existing species of Sorex or Crossopus occur in the Norfolk Forest bed, while an extinct species has been found in the Pleistocene of Sardinia. Crocidura occurs in the cavern-deposits of Madras. Shrews from the Miocene and Upper Eocene of Europe have been referred to Sorex and the genus Amphisorex, which is a synonym of Crossopus.

Family Talpidæ.

Allied to the Soricidæ, but distinguished by the presence of a zygomatic arch and auditory bulla in the skull, and by the form of the teeth. The eyes are very small, and in some species covered with skin; the ears are short and concealed by the fur; the fore limbs are generally more or less modified for digging; there is no symphysis pubis; the intestine has no cæcum; the tibia and fibula are united; and the unicuspidate first upper and lower incisors are not extended horizontally forwards.

This family is connected with the Soricidæ by Urotrichus and Uropsilus. All the members are limited to the temperate regions of Europe, Asia, and North America; and the majority of them are of fossorial habits, although a few are aquatic or cursorial. The family has been divided into two subfamilies by Professor Mivart, and since this arrangement has been very generally adopted it will be followed here. From the presence of intermediate forms like Scaptonyx Dr. Dobson, in the second part of his Monograph of the Insectivora, has proposed a different arrangement, which, with the omission of some forms which are of not more than subgeneric value, is as follows:—

Subfamily Myogalinæ.—Clavicles and humerus moderately elongated; manus without falciform bone.

Myogale.[553]—Dentition: i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; total 44. Feet webbed. Habits aquatic. This genus is represented by the two species M. moschata (Fig. 289) and M. pyrenaica, of which the former is by far the largest member of the family, its total length being about 16 inches. Its long proboscis-like snout projects far beyond the margin of the upper lip; the toes are webbed as far as the bases of the claws; and the long scaly tail is laterally flattened, so as to form a powerful instrument of propulsion when swimming. This species inhabits the banks of streams and lakes in South-East Russia, where its food consists of various aquatic insects. M. pyrenaica, living in a similar manner in the region of the Pyrenees, is very much smaller, has a round tail, and a proportionally longer snout. Fossil remains of M. moschata occur in the Norfolk Forest bed, and were originally described under the name of Palæospalax. The genus is also represented in the Middle and Lower Miocene of the Continent.

Urotrichus.[554]—Dentition: i ²⁄₁, c ¹⁄₁, p ⁴⁄₃ or ³⁄₄, m ³⁄₃; total 36. Feet not webbed; manus broad. Habits fossorial. The Mole-Shrews, as these animals are called, are represented by U. talpoides of the mountains of Japan and U. gibbsi of North America. These two species are small and closely allied animals; the American form (which it has been proposed to separate subgenerically as Neurotrichus) having p ³⁄₄.

Uropsilus.[555]—Dentition: i ²⁄₁, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 34. Manus narrow; tail naked and scaly. Habits cursorial. The single species, U. soricipes, from the borders of Tibet, is a slate-coloured animal with the external form of a Shrew but the skull of a Mole.

Subfamily Talpinæ.—Clavicle and humerus very short and broad; manus with a large falciform bone.

A. First upper incisor much larger than the second (New World Moles).

Scalops.[556]—Dentition: i ³⁄₂, c ¹⁄₀, p ³⁄₃, m ³⁄₃; total 36. Extremity of muzzle simple; hind feet webbed; tail short and nearly naked. Represented by three species in the United States.

Scapanus.[557]—Dentition: i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; total 44. Extremity of muzzle simple. The two North American species of this genus resemble Scalops in general characters, but have a dentition like Condylura. The habits are like those of the latter, and the right to generic distinction is doubtful.

Condylura.[558]—Dentition: i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; total 44. Extremity of muzzle surrounded by filiform appendages. The Star-nosed Mole (C. cristata) derives its name from the star-like ring of appendages at the extremity of the muzzle, with the nostrils in the centre. The general contour is Mole-like, but the tail is nearly as long as the body, and the manus is somewhat less powerful, with its terminal phalanges not cleft. The length of the head and body is about 5 inches. This species is common in parts of North America, and forms tunnels in the ground like the Common Mole.

B. First upper incisor scarcely larger than the second (Old World Moles).

Scaptonyx.[559]—Dentition: i ³⁄₂, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; total 42. Manus moderately broad, as in Urotrichus. Represented only by S. fusicaudatus of Eastern Tibet, which may be regarded as connecting Talpa with Urotrichus, having the head of the former and the limbs of the latter.

Talpa.[560]—Dentition (usually): i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; total 44. Manus extremely broad.

This genus includes the true Moles, of which the common English Mole[561] (T. europæa) is the type. This animal is about 6 inches in total length, of which rather more than one inch is occupied by the tail. The body is elongated and cylindrical, and, owing to the very anterior position of the fore limbs, the head appears to rest between the shoulders; the muzzle is long and obtusely pointed, terminated by the nostrils, which are close together; the minute eye is almost hidden by the fur; the ear is without a conch, and opens on a level with the surrounding integument. The fore limbs are rather short and very muscular, terminating in broad, naked, shovel-shaped feet, with the palms normally directed outwards, and each with five subequal digits armed with strong flattened claws. The hind feet are long and narrow, and the toes are provided with slender claws. The body is densely covered with soft, erect, velvety fur, the hairs being uniform in length and thickness, except on the muzzle and short tail. The colour of the fur is generally black, with a more or less grayish tinge, or brownish-black, but various paler shades up to pure white have been observed.

The food of the Mole consists chiefly of the earth-worm, in pursuit of which it forms its well-known underground excavations. Its habits were many years ago studied and described by M. Henri le Court. Like many other mammals, the Mole has a lair to which it may retire for security. This consists of a central nest formed under a hillock, placed in some protected situation, as under a bank, or between the roots of trees. The nest, which is lined with dried grass or leaves, communicates with the main run by four passages, of which only one joins it directly, leading downwards for a short distance and then ascending again. The other three are directed upwards and communicate at regular intervals with a circular gallery constructed in the upper part of the hillock, which in turn communicates by five passages leading downwards and outwards with another much larger gallery placed lower down on a level with the central nest, from which passages proceed outwards in different directions, one only communicating directly with the main run, while the others, curving round, either soon join or end blindly. The main run is somewhat wider than the animal’s body: its walls are smooth, and formed of closely compressed earth, the depth varying according to the nature of the soil, but ordinarily from 4 to 6 inches. Along this tunnel the animal passes backwards and forwards several times daily, and here traps are laid by mole-catchers for its capture. From the main run numerous passages are formed on each side, along which the animal hunts its prey, throwing out the soil in the form of mole-hills. The Mole is one of the most voracious of mammals, and, if deprived of food, is said to die in from ten to twelve hours. Almost any kind of flesh is eagerly devoured by captive Moles, which have been seen by various observers, as if maddened by hunger, to attack animals nearly as large as themselves, such as birds, lizards, frogs, and even snakes; toads, however, they will not touch, and no form of vegetable food attracts their notice. If two Moles be confined together without food, the weaker is invariably devoured by the stronger. Moles take readily to the water, in which respect they resemble their representatives on the North American continent. Bruce, writing in 1793, remarks that he saw a Mole paddling towards a small island in the Loch of Clunie, 180 yards from land, on which he noticed mole-hills.

The sexes come together about the second week in March, and the young—generally from four to six in number—which are brought forth in about six weeks, quickly attain their full size.

The Mole exhibits in the whole of its organisation a perfect adaptation to its peculiar mode of life. In the structure of the skeleton (Fig. 290) very striking departures from the typical mammalian form are noticeable. Thus the presternum is so much produced anteriorly as to extend forward as far as a vertical line from the second cervical vertebra, carrying with it the very short and almost quadrate clavicle, which is articulated with its anterior extremity and distally with the humerus; being also connected ligamentously with the scapula. The fore limbs are thus brought opposite the sides of the neck, and from this position a threefold advantage is derived: in the first place, as this is the narrowest part of the body, they add but little to the general width, which if increased, would lessen the power of movement in a confined space; secondly, this position allows of a longer fore limb than would otherwise be possible, and so increases its power; and, thirdly, although the entire limb is relatively very short, its anterior position enables the animal, when burrowing, to thrust the claws so far forward as to be in a line with the end of the muzzle, the importance of which is evident. Posteriorly, the hind limbs are similarly removed out of the way by approximation of the hip-joints to the centre line of the body. This is effected by inward curvature of the innominate bones at the acetabula to such an extent that they almost meet in the centre, while the pubic bones are widely separated behind. The shortness of the fore limb is caused by the great reduction in the length of the humerus, which has lost all resemblance to its normal shape. In addition to the usual articulation with the glenoid cavity of the scapula, the humerus also has a separate articulation with the extremity of the clavicle. The bones of the manus are enormously expanded laterally; this expansion being increased by the large sickle-like bone on the radial side of the carpus, which is considered by some anatomists to represent the prepollex. The skull is long and tapering, with very slender zygomatic arches and elongated nasals, which are ankylosed together, and in advance of which the mesethmoid is more or less ossified. The vertebræ are usually C 7, D 13, L 6, S 6, C 10-12; all having very strong surfaces for mutual articulation. The upper incisors are chisel-like, and the canine has two roots; the first three upper premolars are simple and conical, but the fourth is much larger, and canine-like. In the mandible the incisors are small and somewhat proclivous, while the canine can only be distinguished from them by its position: the first lower premolar is larger than the others.

The Common Mole has an exceedingly wide distribution, ranging over the greater part of the Palæarctic region, where it is met with in places so widely sundered as England and Japan. It occurs in both the Himalaya and Altai mountains. In Ireland it is unknown, and in Scotland it extends as far north as Caithness. Eight species of the genus are recognised, which may be grouped, from the characters of their dentition, as follows, viz.: i ³⁄₃, c ¹⁄₀, p ⁴⁄₄, m ³⁄₃, T. wogura; i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃, T. europæa, cæca, longirostris, micrura; i ³⁄₃, c ¹⁄₁, p ³⁄₄, m ³⁄₃, T. leucura, leptura; i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃, T. moschata.

Except in T. europæa, the eyes are covered by a membrane. In T. micrura the short tail is concealed by the fur. T. cæca is found south of the Alps; the remaining species are Asiatic, and two only—T. micrura and T. leucura—occur south of the Himalaya. T. moschata, of Tibet, is regarded by some zoologists as generically distinct under the name of Scaptochirus.

Remains of T. europæa occur in the Norfolk Forest bed, while extinct species are found in the European Tertiaries as far down as the Lower Miocene, although it has been proposed to separate some of these forms generically. Protalpa, of the Upper Eocene Phosphorites of Central France, is very closely allied, but the structure of the humerus is somewhat less specialised.

Extinct Genera.—A number of extinct Insectivora from the European Tertiaries more or less closely allied to the Moles have been described, but since our knowledge of most of them is extremely imperfect their precise affinities are in many instances problematical. Of these, the Lower Miocene Tetracus is said to have affinity both with Myogale and Erinaceus; while the forms described as Mysarachne and Echinogale, are considered to connect the present with the two preceding families. Plesiosorex is another Lower Miocene type known only by the mandible, in which there are ten teeth; it is generally referred to the Myogalinæ. The minute Amphidozotherium, of the French Phosphorites, is considered to be allied to Urotrichus.

Family Adapisoricidæ.

This extinct family is represented by the genera Adapisorex and Adapisoriculus, of the lowest Eocene of Rheims, which are regarded as allied to the Soricidæ, but somewhat more specialised. In the type genus the formula of the lower teeth is i 2, c 1, p 4, m 3; the incisors and canine being proclivous, and the molars (of which the last is small and without a third lobe) quadritubercular. Adapisoriculus is a smaller form with differently shaped molars.

Here also may be mentioned the genera Orthaspidotherium and Pleuraspidotherium, from the above-mentioned deposits, which are probably members of the present order. They appear to have been animals somewhat smaller than a Hedgehog, with quadritubercular upper molars (Fig. 291), and the hinder premolars more complex than those of the Erinaceidæ. In the first-named genus the dental formula is i ³⁄₃, c ¹⁄₁, p ⁴⁄₄, m ³⁄₃; the third and fourth upper premolars having one outer column. Pleuraspidotherium has apparently only three premolars, of which the third and fourth (Fig. 291) have two outer columns. The humerus in both has no entepicondylar foramen, the femur has a third trochanter, and the astragalus is vertically perforated.

Family Potamogalidæ.

Skull with a small brain-case, no zygomatic arch or postorbital process, and the tympanic annulate and not forming a bulla. Upper molars with the cusps arranged in a broad V, and somewhat intermediate in structure between those of the preceding and succeeding families. No clavicle; pubic symphysis ligamentous; tibia and fibula typically united distally. No cæcum. Confined to the Ethiopian region.

Potamogale.[562]—Dentition: i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 40. Represented only by P. velox of Western Equatorial Africa. This animal (Fig. 292) inhabits the banks of streams, and is thoroughly adapted for an aquatic life; it is nearly 2 feet in length, the tail measuring about half. The long cylindrical body is continued uninterruptedly into the thick laterally compressed tail, the legs are very short, and the toes are not webbed, progression through the water evidently depending wholly on the action of the powerful tail, while the limbs are folded inwards and backwards. The muzzle is broad and flat, and the nostrils are protected by valves. The fur is dark brown above, the extremities of the hairs on the back being of a metallic violet hue by reflected light, beneath whitish. This curious animal was discovered by M. du Chaillu.

Geogale.[563]—Dentition: i ²⁄₂, c ¹⁄₁, p ³⁄₂, m ³⁄₃; total 34. This genus is known solely by G. aurita, a small Mouse-like species from Madagascar, agreeing closely with Potamogale in the general form of the skull and teeth. The tibia and fibula are distinct, but it is not known whether a clavicle exists; and the material at present available is insufficient to definitely fix the natural position of the genus.

Family Solenodontidæ.

Skull with a small brain-case constricted between the orbits, no zygomatic arch or postorbital process, and the tympanic annulated and not forming a bulla. Upper molars tritubercular, the cusps being arranged in a V. Pubic symphysis short; tibia and fibula distinct. Vertebræ: C 7, D 15, L 4, S 5, C 23. No cæcum. The penis is carried forwards and suspended from the abdomen; the testes are received into perineal pouches; the mammary glands are post-inguinal; the uterine cornua end in cæcal sacs.

Solenodon.[564]—Dentition: i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 40. This genus, with S. paradoxus and S. cubanus (Fig. 293), from Hayti and Cuba respectively, alone represents the family. These species, which differ chiefly in the colour and quality of the fur, have a remarkably long cylindrical snout, a long naked tail, feet formed for running, and the body clothed with long, coarse fur.

The position of the mammæ quite behind on the buttocks is unique among Insectivora. The first upper incisor is much enlarged, and this and the other incisors, canines, and premolars, closely resemble those of Myogale; the second lower incisor is, as in Potamogale, much larger than the anterior one, and is deeply hollowed out internally. While thus apparently showing relationship with the Talpidæ, the form of the crowns of the molar teeth connects them with the next family.

Family Centetidæ.

Skull (Fig. 294) with a small cylindrical brain-case not constricted between the orbits, no zygomatic arch or postorbital process, and the tympanic annulate and not forming a bulla. Upper molars tritubercular. Pubic symphysis short; and the tibia and fibula either united or free. No cæcum. The penis is pendent and retractile within the fold of the integument surrounding the anus; the testes are abdominal; the mammæ are thoracic and ventral; and the uterine cornua are terminated by the Fallopian tubes. All the species are limited to Madagascar.

Subfamily Centetinæ.—Tibia and fibula distinct; testes near kidneys; fur with spines.

Centetes.[565]—Dentition: i ²⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 38. Vertebræ: C 7, D 19, L 5, S 3, C 8. The single species is the well-known Tenrec (C. ecaudatus), characterised by the absence of a tail; it reaches a total length of from 12 to 16 inches, and is the largest known Insectivore. The adult males have long canines, the extremities of the lower pair being received into pits in front of the upper ones (Fig. 294). It is probably the most prolific of all mammals, since as many as twenty-one young are said to have been brought forth at a birth. The young have strong white spines arranged in longitudinal lines along the back, but these are lost in the adult animal, which is provided only with a nuchal crest of long rigid hairs. In rare instances a fourth upper molar may be developed.

Hemicentetes.[566]—Dentition: i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 40. This genus is represented by the two species H. semispinosus (of which the skull is shown in Fig. 295) and H. nigriceps. It differs from Centetes by the presence of the third upper incisor, the much smaller canines, and by the form of the skull. Both species are very much smaller than C. ecaudatus, and the dorsal spines are retained in the adult state. Vertebræ: C 7, D 16, L 5, S 3, C 9.

Ericulus.[567]—Dentition: i ²⁄₂, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 36. Vertebræ: C 7, D 17, L 6, S 4, C 9. The single species, E. setosus, is a Hedgehog-like animal, having the whole upper surface and the short tail densely covered with close-set spines. The facial bones are much shorter than in any of the preceding genera, and the first upper incisor is elongated, as in Erinaceus. Judging from the slight development of the cutaneous muscles compared with those of the true Hedgehogs, it is probable that complete involution of the body does not take place.

Subfamily Oryzorictinæ.—Tibia and fibula united; testes near urethra; fur without spines.

Microgale.[568]—Dentition: i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁄₃; total 40. This genus includes M. longicaudata and M. cowani, both of which are small Mouse-like species, the former with a tail double the length of the head and body, and having 43 caudal vertebræ; teeth like those of Centetes ecaudatus, but, owing to the comparatively much shorter muzzle, not separated by wide spaces, and the last premolar and molar with internal basal processes.

Oryzorictes.[569]—Represented by two species, O. hova and O. tetradactylus, the latter distinguished by the presence of only four digits in the manus, the three inner having long laterally compressed fossorial claws. The general form of the head and body of the two species known is like that of a Mole. These animals burrow in the rice-fields and do much damage to the crops.

Family Chrysochloridæ.

Skull conical, not constricted between the orbits, without postorbital process, but with well-developed zygomatic arch and tympanic bulla. Upper molars tritubercular, with the crowns very tall. No pubic symphysis; the tibia and fibula united. The eyes are covered by the hairy integument; the ears short and concealed by the fur; the internal generative organs are as in Centetinæ; the mammæ are thoracic and inguinal and placed in cup-shaped depressions. Habits fossorial. Confined to the southern part of the Ethiopian region, not extending to Madagascar.

This family is closely allied to the Centetidæ, occupying the same relative position with respect to that family that the Talpidæ does to the Soricidæ. Compared with the Talpidæ, we find the following differences in the structural adaptation to a fossorial life; the manubrium sterni is not anteriorly elongated, neither are the clavicles shortened; but this is compensated for by a deep hollowing out of the antero-lateral walls of the thorax, the ribs in these parts and the sternum being convex inwards. The long clavicles have their distal extremities pushed forward, and the concavities on the sides and inferior surface of the thorax lodge the thick muscular arms.

Chrysochloris.[570]—Dentition: i ³⁄₃, c ¹⁄₁, p ³⁄₃, m ³⁻²⁄₃₋₂; total 40 or 36. Vertebræ: C 7, D 19, L 3, S 5, C 8. This genus includes some seven or eight South African species, commonly known as Golden Moles (Fig. 296). Those species, in which the molars are reduced to ²⁄₂, with a basal talon to the lower ones, and without a prominence in the temporal fossa, have been placed in a separate genus, Chalcochloris, by Professor Mivart. Nearly all the species have the fur of the upper surface of a brilliant metallic lustre, varying from golden bronze to green and violet of different shades. The manus has four digits, of which the two outer are small, while the middle ones are large, with immensely powerful claws.

Extinct Types.—The only fossil forms which can be referred to the section of the Insectivora with tritubercular molars are the Leptictidæ, of the Eocene and Miocene of North America. This family includes the genera Leptictis, Mesodectes, and Ictops, all of which are regarded by Dr. Schlosser as true Insectivora, although they were placed by Professor Cope with the Creodont Carnivora.