Page:Encyclopædia Britannica, Ninth Edition, v. 15.djvu/425

Rh INSECTIVOIiA.] MAMMALIA 403 F.G. 57 . Skull and Dentition of Sorex verx- Alston, Proc. Zool. Sue., 1877. I-nscctivora referred to in the bibliography). The common Hedgehog (K. europeeus) is the most aberrant species, differing from all the rest in the peculiarly shaped and single-rooted third incisors and first upper premolars (fig. 56, A), and in its very coarse harsh fur. The dentition of the long-eared North Indian form, E. grayi (fig. 56, B), may be considered characteristic of all the other species, I he only important differences being found in the variable size and position of the second upper premolar, which is very small, external, and deciduous in the Indian species E. micropus and pictus. The former species, limited to South India, is further distinguished by the absence of the malar bone. Of African species, E. diadcmatus, with long frontal spines, is probably the commonest, and E, albiventris has been made the type of a separate genus on account of the total absence of the hallux. Family SOKICID^E. Terrestrial, rarely natatorial, Insectivora, with narrow elongated skulls, without post-orbital processes or zygomatic arches. The tympanics are annular, not forming bullre ; there is no symphysis pubis ; the intestine has no caecum ; the tibia and fibula are united ; and the molars have well-developed W-shaped cusps. The dentition is very characteristic of the family ; in all the upper front incisors are large, with a more or less prominent posterior basal cusp, and be tween these and the last pre-. ff^r, molar intervene a variable number of small incisors and preraolara, among which the small canine can be distin guished only by its position immediately behind the pre- maxillary suture. The number of teeth in the mandible is always twelve, and the single pair of incisors are much ex tended horizontally forwards, the canine is the smallest tooth, and the single pre molar is not much larger (see fig. 57). The Shrews thus form a very compact family, which includes considerably more than half the known species of Insectivora, and of which the geographical distribution is coextensive with that of the order. They have been divided into several genera (so-called) and subgenera, depending chiefly on the number of the upper incisors and premolars, and on the colour of the teeth. The best arrangement appears to be that proposed by M. Alph. Milne-Edwards, as follows : A. Terrestrial ; feet without a border composed of stiff hairs. ( a&quot;. Tail very short, concealed. 1. Anourosorex. Tail moderately long. 2. Diplomesodon. U . 28-30 teeth. 3. Croddura. b. Teeth more or (. Tail short ; ears small. 4. Blarina. less brown &amp;lt; b. Tail and ears moderately long, or red. ( 5. Sorex. B. Amphibious ; feet with a bonder of stiff hairs. a Feet not ( a&amp;gt; 32 teetn ; na i rs f tail equal. 6. Ncosorcx. webbed j ** ^ teeth ; tail fringed along middle edge. ( 7. Crossopus. b. Feet webbed. 8. Ncctogale. Anourosorex includes A. squamipes, a Mole-like species, with very short ears and tail, from Tibet. Diplomesodon, with one species, D. pulchcllus, from the Kirghiz steppes, though agreeing in the number of teeth, is Shrew-like in external form. Croddura, 28-30 teeth, with about seventy species divided into four subgenera, comprises the greater number of white-toothed Old-World Shrews having a round tail thinly clothed with a few hairs of unequal length. C. aranca and G. suavcolens of the continent of Europe, and C. indicus, the Musk-Rat of India, are well-known examples! Sorex, the typical genus (see SHREW), also divided into four sub- genera, with Blarina, includes all the species with brown teeth and angular uniformly hairy tail. Ncosorcx includes the New-World and Crossopus (see SHREW) the Old-World amphibious species, hav ing a fringe of stiff hairs along the sides of the feet, and Ncctogale a very remarkable species from Tibet, N. clcgans (fig. 58), distin guished from all other Shrews by the webbed condition of the toes, and the presence of adhesive cushions on the under surface of the feet, which enable the animal to hold on to smooth stones at the bottom of rushing torrents. Family TALPID.E. Fossorial, rarely natatorial, Insectivora, distinguished from the Soriddss by the presence of zygomatic arches and tympanic bullse ossece, and by the form of the teeth. The eyes are very small, in Teeth white. 26 teeth. 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 csecum ; the tibia and fibula are united ; and the unicuspidate upper and lower front incisors are not extended horizontally forwards. FIG. 5S.-Nectoyale eler/ans. A. Milne-Edwards, Mammif. Tilet. This family, though thus easily distinguished, is, nevertheless, evidently closely related to the Shrews, with which such inter mediate forms as those included in the genera Urotrichus and Uropsilus connect it. In striking contrast with the Shrews, however, the distribution of the Moles is limited to the temperate regions of Europe, Asia, and North America. Subfamily I. Myogalinae. Clavicles and humeri moderately elongated ; manus without os falciforme. a. i f, c $, pm, m f ; feet webbed ; natatorial. Myogale. b. i, c -J-, pm f , m f ; feet narrow ; terrestrial. Uropsilus. c. i f, c ^, pin or f, in f ; feet wide ; fossorial. Urotrichus. Myogale includes two very remarkable species, M. moschata and M. pyrenaica. The former is by far the largest species of the FIG. 59. Myoyale moschata. x J. 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, forming a powerful instrument of pro pulsion 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 mucli smaller, has a round