758 MAMMALIA. 



of the upper jaw, and i. 3, c., pm. 3, m. 1-3, of the lower 

 jaw, are persistent milk-teeth, but, according to others, the 

 milk-teeth are represented by mere rudiments ("prelacteal 

 germs "), and the functional teeth correspond to the perma- 

 nent 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, 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 uterus. Several and usually many 

 offspring 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. In the former continent their place is taken by 

 the insectivorous opossums. 



Examples. The hedgehogs (Erinaceus], throughout Europe, 



and most of Asia, dentition 3TJ - ; the shrews (So rex), in Europe, 



2123 



Asia, and N. America, dentition ^^ ; the moles (Talpa), through- 

 out the Palrearctic region ; the tailless tenrec ( Centetes] of Mada- 

 gascar ; the S. African golden moles (Chrysochloris) ; the African 

 jumping shrews (Macroscelides) ; the Oriental tree-shrews (Tupaia). 



Order GALEOPITHECID/K. 



It seems justifiable to recognise a separate order for the very 

 divergent Galeopithecus, from the Malay Archipelago and the 

 Philippines. They are arboreal vegetarian animals. The fore- and 

 hind-limbs are connected by a parachute, and the animals can glide 

 from tree to tree, "sometimes traversing a space of seventy yards with 

 a descent of only about one in five." The structure of the incisors 

 is unique among Mammals. They are expanded laterally, compressed 

 from before backwards, and furnished with many cusps. The lower 



