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642
INSECTIVORA


organs and the vent, although close together, are yet distinct. In the musk-shrews (Crocidura), on the other hand, which are common to Europe, Asia and Africa, the reproductive organs and the alimentary canal discharge into a common cloaca, the long tail is sparsely covered with on and short hairs, there are anal glands secreting a strong musky ffuid, and the number of upper teethis X6 or 18. Diplomesodon pulchellus of the Kir hiz steppcs, has, on the other hand, only 14 upper teeth, and is further characterized by the moderately long tail and the hairy soles of the hind-feet. Another genus is represented by the Tibetan Anurosorex squamipes, which has pared to a giant shrew, and whose colour is partly black and artly white, although a uniformly pale-coloured race. (G. r. alba) inlfiabits Borneo. In common with the next genus, it has the full series of 44 teeth; and its range extends from Tenasserim and the Malay Peninsula to Sumatra and Borneo, the island individuals being stated to be considerably larger than those from the mainland. In this species the length of the tail is about three-fourths that of the head and body; but in the lesser rat-shrew (Hylomys suillus), ranging -s-v*~,

the same ental formula, but a mole-like form, rudimentary tail and r, M i' w r., scaly hind-soles. Lastly, we have two Asiatic mountain aquatic ' 4' " sgecies, Chimarrogale hrmalayaca of the Himalayas and Nectagale ~, e gans of Tibet, which have fringed tails like the European water- mtgshrew, and 16 upper teeth, the former characterized by the small but s ish.; ' '~ ~ ' perfect external ears, and the latter (fig. 6) by the absence of the ears A, Y § "~.n, Q§ , tt ' *~ fi and presence of adhesive disks on the feet. * TT , » . f (, V It will be seen that the red- and the white-toothed series have C ", Q parallel representative forms, which may indicate that the division lW~ , ' if of the family into the two grou s is one based rather on convenience » *irifn, ,, an Y* it* $ than inessential differences. See SHREW. “' l" F rom the shrews, the hedgehogs and gymnuras, or rat-shrews, collectively forming the family Erinaceidaz, differ structurally by the broader ring made by the tympanic, the complete zygomatic arch, the five-cusped broad upper molars, and the presence of a short -5.

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FIG. 6.-The Tibetan Water-shrew (Nectogale el¢gans). wbic symphysis. At the present day they are an exclusively Old orld group.

The typical group, or Efinaceinae, is represented onl by the hedgehogs, with the one genus Erinaceus, easily recognized/ by their spiny coats, and further characterized by the rudimentary "°"3°° tail, the pfesence of vacuities in the palate, and the broad "W" pelvis. edgehogs (Erinaceus) have the dental formula i, {, ¢ }, p. Q, m. § , and are represented by over a score of s ecies, distributed throughout Europe, Africa and the greater part oi) Asia, but unknown in Madagascar, Ceylon, Burma, Siam, the Malay countries, and, of coursef Australia. All the species resemble one another in the armour of spines covering the upper surface and sides of the body; and all possess the power of rolling themselves up into the form of a ball protected on all sides by these spines, the skin of the back being brought downwards and inwards over the head and tail so as to include the limbs by the action of special muscles. (furiously enough the European hedgehog (E. europaeus) is the most aberrant species, differing from all the rest in the peculiarly-shaped and single-rooted third upper incisor and first premolar (fig. 7, A), and in its very coarse harsh fur. The dentition of the long-eared Indian E. grayi (fig. 7, B) may, on the other hand, be considered characteristic of all the other species, the only important differences being found in the variable size and position of the second upper remolar, which is very small, external and deciduous in the Indian E. micfopus and E. pictus. The former species, limited to South India, is further distinguished by the absence of the jugal bone. Of African species, E. diadematus, 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 first front-toe. See HEDGEHOG.

The members of the second subfamily, Gymnurfinae, are more or less rat-like animals, confined to the Mala countries, and easily distinguished from the hedgehogs by the absence of spines Rn' among the fur and the well-developed tail. They also lack h""" vacuities in the palate, and have a long and narrow pelvis. The typical representative of the family is the greater rat-shrew, or greater gymnura (Gymnura rajlesi) a creature which may be com-FIG. 7.—Fore-part~ of -Skulls of Common Hedgehog (Erinaceus europaeus), A, and Gray's Hedgehog (E. grayi), B, much enlarged. from Burma and the Malay Peninsula to ]ava and Sumatra, the former dimension is only about one-sixth of the latter. In the Philippines the roup is represented by Podogymnura truei, distinguished from tie other genera by the great elongation of the hindfoot, the tail being likewise long. There are only three pairs of premolars in each jaw.,

In the remaining families of the Insectivora the tibia and fibula may be either separated or united at the lower end; there is no descent of the testes, except in Solenodon; a short symphysis is formed by the j-unction of the pubic epi- ""°"'" physes; and the upper molars are generally small, and;°""'s triangular, with three cusps arranged in a V. The first “er” family, Potamogalidae, is represented by the otter-like Potamogale velox of the rivers of West Africa (fig. 8), distinguished from all other F IG. 8.-T he Insectivorous Otter (Potamogale velox). > members of the order by the absence of clavicles. The tibia and fibula are uniteo inferiorly, the skull has a ring-like tympanic, no zygomatic arch, and the vpper molars are of the tuberculo-sectoral type, with broader crowns than in the following families. The dental formula is i. § , c. }, p. § , m. § , total 40. This animal inhabits the banks of streams in west equatorial Africa, and its whole structure indicates an aquatic life. It is nearl 2 ft. in length, the tail measuring about half. The long cylinciiical 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 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