CHAPTER XII 
THE ORDER INSECTIVORA 
THE Insectivora comprise a number of comparatively small mam- 
mals, generally of terrestrial, although rarely of arboreal or aquatic 
habits, and presenting the following common features. They are 
unguiculate, and have plantigrade or subplantigrade, and generally 
pentadactylate feet, in which the pollex and hallux are not oppos- 
able to the other digits. They are diphyodont and heterodont, and 
the teeth are rooted. The molars are studded with sharp cusps, 
the crowns of the upper molars being either quadrangular or trian- 
gular; there are never less than two incisors in either side of the 
mandible ; and in many cases the incisors, canines, and anterior 
premolars are not clearly differentiated from one another (Fig. 280) ; 
the canines being 
usually weak. 
Clavicles are pre- 
sent, except in 
Potamogale. The 
body is clothed 
with fur or pro- 
tected by an 
armature of 
spines; the 
Fie. 280.—Right lateral aspect of the anterior portion of the 5% . 
cranium of Lrinaceus collaris. Enlarged. (From Dobson, Proc. Zool. tes tes are in- 
Soc. 1881, p. 403.): eninal or placed 
near the kidneys, 
and are not received into a scrotum; the penis is pendent or sus- 
pended from the wall of the abdomen; the uterus is two-horned 
and with or without a distinct corpus uteri; the placenta is dis- 
coidal and deciduate ; and the smooth cerebral hemispheres do not 
extend backwards over the cerebellum (Fig. 281). The projee- 
tion of the muzzle far beyond the extremity of the lower jaw is a 
very general feature. The humerus generally has an entepicondylar 
