Page:Encyclopædia Britannica, Ninth Edition, v. 15.djvu/427

Rh C HIROPTERA.] M A M M A L.I A 405 Hedgehogs, it is probable that complete involution, as in the latter animals, does not take place. IG. 63. Skull Jfi-miccnti tes temitpinosut, x 2. Alivart, J roc. Zool. Soc., 1871. Subfamily II. Oryzorictinee. Tibia and fibula united ; testes near urethra ; fur without spines. Microgale, if, c^, pm f, m f , includes M. longicaudata and M. cowani, small Mouse-like species, the former with a tail double the length of the head and body ; teeth like those of C. ecaudatus, but, owing to the comparatively much shorter muzzle, not separated by wide spaces, and the last premolar and molars with internal basal processes. Oryzorides contains 0. hova and 0. tetradadylus, the latter distinguished by the presence of four digits only 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 that of a Mole. They burrow in the rice-fields, and do much damage to the crops. Family CHRYSOCIILORIDJE. Fossorial Insedirora, with conical skulls not constricted between the orbits, with well-developed zygomatic arches and tympanic bulloe, but without post-orbital processes. The eyes are covered by the hairy integument, the ears short and concealed by the fur ; the internal generative organs and the crowns of the upper molar teeth are as in Centetinse ; the mammary teats are thoracic and inguinal, and placed in cup-shaped depressions ; there is no pubic symphysis ; and the tibia and fibula are united. This family is evidently closely allied to Centetidse,, occupying the same relative position with respect to that family that Talpidse does to Soricidee. All the species are fossorial, and restricted to south Africa. In all the forearm and manus are similarly modified for digging, but in a manner very different from that observable in (see MOLE). FIG. &amp;lt;&amp;gt;l. (Ihrysoehlorit vbtusirvstris (reduced). Chrysochloris, i f, c, pm |, m f or , embraces seven or eight species. Those with m f, with a basal talon to the lower grinders, and without a prominence in the temporal fossa, have been placed in a separate genus Calcochloris 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. FOSSIL INSECTIVORA. Of fossil Insectivora no undoubted traces have been found in deposits earlier than the Eocene. Amphidozotherium, allied to Urotrichus, and Neogymnurus and Protalpa, with relationships to Gymnura and Talpa respectively, have been described from the lacustrine Eocene beds of Quercy. Several genera with insectivorous affinities have been characterized by Cope and Marsh from remains found in the Eocene of Wyoming, but these, have been relegated to distinct suborders of a new order Bunodonta, of which Insedivora is considered a suborder only. The Miocene deposits of the south of France and Germany have yielded fossil forms of Erinaceidae, (Amphcchinus, Galcrix, Tetracus), of Soricidse. (Sorcx, Mysarachne, Plcsiosorex), and of Talpidse, (Dimyliis, Galcospalax, Gcotrypus, Jlyporissus, Myogalc). Of the latter family Galcospahix has been characterized from the Pliocene of Norfolk ; and remains of the common Hedgehog, and of some of the existing species of Sorex, have been found in various post-Tertiary deposits. nibHograpliii of Insectivora. Peters, Reise nach Mossambique Saugeth., 18o2; Id., &quot; Ueber die Clas&amp;gt;ification dor Insectivora,&quot; Monatsb. Akad. Wisaentdi. flerlin, 18G5, and other papers ; Mivart, &quot;On the Osteology of the Insectivora,&quot; Jour. Anat. and Phi/s., 1867. 18fi8, and Proc. Zool. Soc., 1871 ; Gill, &quot;Synopsis of Insectivorous Mammals,&quot; Bull. Geol. and Geog. Survey, U.S.A., Washington, 1875 (includes a general bibliography of the order Instctivora) ; Dobson, Mono graph of the Insectivora, Systematic and Anatomical, London, 1882. OKDEK CHIROPTERA. Volant mammals, having their fore limbs specially modified for flight. The forearm consists of a rudimentary ulna, a long curved radius, and a carpus of six bones supporting a thumb and four greatly elongated fingers, between which, the sides of the body, and the hinder extremities a thin expansion of the integument (the wing- membrane) is spread out. The knee is directed backwards, owing to the rotation of the hind limb outwards&quot; by the wing-membrane ; a peculiar elongated cartilaginous process (the calcaneum or calcar), rarely rudimentary or absent, arising from the inn er side of the ankle-joint, is directed inwards, and supports part of the posterior margin of an accessory membrane of flight, extending from the tail or posterior extremity of the body to the hinder limbs (the inter-femoral membrane). The penis is pendent ; the testes abdominal or inguinal ; the mammary glands thoracic and generally post-axillary ; the uterus simple cr with more or less long cornua; the placenta discoidal and deciduate ; and the smooth cerebral hemispheres do not extend backwards over the cerebellum. The dental series consists of four kinds of teeth incisors, canines, premolars, and molars ; and the dental formula never exceeds i, c y, pm , m ; total 38 teeth. The animals comprised in this order are at once distinguished by the presence of true wings, and this peculiarity is accompanied by other modifications of bodily structure having special relation to aerial locomotion. Thus, in direct contrast to all other mimmals, in which locomotion is chiefly effected by action from behind, and the hind limbs consequently greatly preponderate in size over the fore, in the Chiroptera the fore limbs, being the only agents in propelling the body forward during flight, immensely exceed the short and weak hinder extremities; the thorax, giving origin to the great muscles which sustain flight, and containing the proportionately (com pared with other mammals) very large lungs and heart, is remarkably capacious, and the ribs are flattened and close together; the shoulder-girdle is also greatly developed in comparison with the weak pelvic bones. Linnaeus included the Bats among the Primates, mainly on account of the number of their upper incisors, supposed to be always four, the thoracic position of the mammae, and the pendent condition of the penis. Many other zoologists, taking into consideration also the placental characters and the form of the uterus, have followed him ; but it is evident that the situation of the mammas is related to the necessarily central position of the young during flight, the shortness of the uterine cornua, observable in so many species, to the generally uniparous gestation requiring less room, while the discoid deciduate placenta is equally present in and characteristic of the Insectivora, many species of which have also the penis pendent. Then, all these reasons for maintaining the Bats in such an exalted position being disposed of, we find in the low organization of their brain another proof of their inferior position in the zoological sc lie, while furthermore, although they differ