INSECTIVORES 



875 



mc. 



facial region is long ; the zygomatic arch is slender or 

 incomplete. Except in Potamogale, there are clavicles. 



There are never fewer than two pairs of lower incisors. 

 The enamelled molars have tuberculated crowns and well- 

 developed roots. In many 

 cases it is not easy to dis- 

 tinguish the usual division 

 of the teeth into incisors, 

 canines, premolars, and 

 molars, but in many the 

 dentition is typical — 



3> i,4>3=44- 



In the hedgehog, accord- 

 ing to Leche, i. 3, pm. 2, 

 m. 1-3, of the upper jaw, 

 and i. 3, c, pm. 3, m. 1-3, 

 of the lower jaw, are per- 

 sistent milk-teeth, but, ac- 

 cording to others, the milk- 

 teeth are represented by 

 mere rudiments (" prelac- 

 teal germs "), and the func- 

 tional teeth correspond to 

 the permanent set of other 

 mammals. 



The cerebral hemispheres 

 are smooth, and leave the 

 cerebellum (and sometimes 

 the corpora quadrigemina) 

 uncovered ; the olfactory 

 lobes are large ; the corpus 

 callosum is short and thin. 

 Thus, as regards the brain, 

 the Insectivora represent a 

 low grade of organisation. 



The stomach is a simple sac ; the intestine is long and 

 simple, but the vegetarian forms have a caecum. In most 

 there are odoriferous glands, lateral in shrews, but usually 

 near the anus. 



The testes are inguinal or in the groin, or near the 

 kidneys, not in a scrotum. The penis may be pendent 



Fig. 518. — The fore-arm and hand 

 of the mole. — From a Specimen. 



O.P., Olecranon process of ulna (U.) ; 

 R., radius ; C, shaded, the usual two 

 rows of carpal or wrist bones ; P., 

 pisiform, a " sesamoid " bone ; MC, 

 the line passes through four meta- 

 carpals ; I.-V., the claws of the five 

 digits. The claws, coloured dark, are 

 borne by the terminal phalanx of each 

 digit, but this is not shown separately 

 in the diagram. S.B., Special " sickle 

 bone." 



