510 SPINELESS }HEDGEHOGS ; CHAP. 
The under surface of the tail is rough, and it is thought by 
Dr. Blanford that it may be of use to the animal in climbing. 
Its compressed terminal third and the fringe of stiff bristles on 
the under surface of this indicate, according to Dr. Dobson, 
powers of swimming, or at any rate a not very remote ancestry 
of swimming creatures. It is purely insectivorous in diet. 
Erinaceus, including the Hedgehogs, is a widely distributed 
genus—Palaearctic, Oriental, and Ethiopian in range. There are 
about twenty species. The familiar spines distinguish the Hedge- 
hogs from their allies, as also the fact that they possess but thirty- 
six teeth, the formula being 13 C+ Pm3 M3. There are fifteen 
or fourteen ribs, and the tail is very short, consisting of only 
twelve vertebrae. As in Gymnura there is no caecum. The upper 
canine has usually, as in other Erinaceidae, two roots, but not in 
E. europaeus, which is one of the most modified of Hedgehogs. 
The Hedgehog is a more omnivorous creature than Gymnura. 
It eats not only insects and slugs, but also chickens and young 
game birds, and lastly vipers. Four, or in some cases as many 
as five or six, young are produced at a birth; they are blind, 
with soft and flexible white spines. In hot and dry weather 
Hedgehogs disappear; they come forth in rainy weather. The 
English Hedgehog, as is well known, hibernates. The Indian 
species do not. The Hedgehog is occasionally spineless, which 
condition may be regarded as an atavistic reversion.’ 
The Hedgehog has acquired the reputation of carrying off apples 
transfixed upon its spines. Blumenbach thus quaintly describes 
this and other habits‘of the animal, whose English name he gives 
as “hedgidog”: “Il se nourrit des productions des deux regnes 
organisés, miaule comme un chat, et peut avaler une quantité 
énorme de mouches cantharides. Il est certain qwil pique les 
fruits avec les épines de son dos, et les porte ainsi dans son 
terrier.”? 
The Miocene Palaeoerinaceus is so little different from 
Erinaceus that it is really hardly generically separable. 
Evrinaceus is therefore clearly one of the oldest living -genera 
of mammals. 
Necrogymnura of the same epoch and the same beds (Quercy 
Phosphorites) is doubtless an ancestral form. The palate 4s 
1 See Natural Science, xiii. 1898, p. 156. 
2 Manuel d@ Hist. Nat. French trans. by Artaud, 1803. 
