7i8 MAMMALIA. 



There are more than two incisors in the mandible. The 

 enamelled molars have tuberculated crowns and well-de- 

 veloped 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. I. 4, 3=44- 



In the hedgehog, accordmg 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 persistent milk teeth, — a mixed and primitive condition. 



The cerebral hemispheres are smooth and leave the 

 cerebellum 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. 



Except in Galeopithecus, the stomach is a simple sac ; the 

 intestine is long and simple, but the vegetarian forms have a 

 CEecum. In most, there are odoriferous glands, axillary 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 

 from the wall of the abdomen, but is usually retractile. 

 There is a bicornuate or two-horned uterus. Except in 

 Galeopithecus, several offspring and usually many are born 

 at once. 



The allantoic placenta is discoidal and deciduate. There 

 is a provisional yolk sac placenta. 



Insectivora are represented in the!temperate and tropical 

 zones of both hemispheres, but not in S. America nor 

 Australia. 



Sub-Order Insectivora Vera : — Insectivores with free limbs suited for 

 movement on land, climbing, burrowing, or swimming. "The upper 

 and lower incisors are conical, unicuspidate or with basal cusps only, 

 the lower not pectinated." 



Examples : — the hedgehogs (Eriiiacciis), throughout Europe, Africa, 



and most of Asia, dentition ; the shrews (Sore.x), in Europe, 



2123 



4123 

 Asia, and N. America, dentition — ; the moles (Talpa), 



2013 

 throughout the Patearctic region ; the tailless tenrec ( Cen/etes) 

 of Madagascar; the S. African golden moles (Ckiysochloj-is) ; 

 the African jumping shrews (Maii-os<\-/i,ii-s) ; the Oriental tree 

 shrews ( Tttpaia). 

 .Sub-Order Dermoptera : — represented by the very divergent Galeopi- 

 thccjis, which almost requires an order for itself The fore and hind 



