722 MAMMALIA. 



The common seal [Phoca), ~^, the grey seal {Halicharus), 

 the monk seal {Monachus), the large elephant seal {Macrorhinus 

 leoninus). 



Sub-Order Creodonta (extinct). 



In Eocene and early Miocene strata, in Europe and America, there 

 are remains of what seem to be generalised Carnivora, ancestral to the 

 modern types, and apparently related to Insectivora as well. Those 

 included in the sub-order Creodonta have strong canines but no single 

 carnassials, while the molars are often like those of Marsupials. The 

 brain seems to have been small. 



Examples. — Hytenodon, Proviverra, Arctocyon. 



Order Insectivora. 



This order includes hedgehog, mole, shrews, and related 

 mammals. There is much diversity of type, so that a state- 

 ment of general characters is very difficult. 



Most Insectivores run about on the earth ; the mole 

 (Talpa), and others like it, are burrowers ; Potamogale, 

 Myogale, and others are aquatic : Tupaia and its relatives live 

 like squirrels among the branches ; and the aberrant " flying 

 Lemur " — Galeopithecus — takes swoops from tree to tree. 



Most feed on insects, but Galeopithecus and some other 

 arboreal forms eat leaves as well ; the moles eat worms ; 

 Potamogale is said to feed on fish. 



The body is usually covered with soft fur, but the hedge- 

 hog (Erinaceus) is spiny, and so to a less extent is Centetes, 

 the groundhog of Madagascar. The digits, usually five in 

 number, are clawed, and the animals walk in plantigrade 

 or semi-plantigrade fashion. In most, the mamma? are 

 thoracic or abdominal ; in Galeopithecus there are two pairs 

 in the axillary region. 



The cranial cavity is small ; the skull is never high ; the 

 facial region is long ; the zygomatic arch is slender or 

 incomplete. Except in Potamogale, there are clavicles. 



There are never less than two pairs of lower incisors. 

 The enamelled molars have tuberculated crowns and well- 

 developed roots. In many cases it is not easy to distinguish 

 the usual division of the teeth into incisors, canines, pre- 

 molars, and molars, but in many the dentition is typical — 

 3, h 4, 3=44- 



