COUES ON GEOMYS AND THOMOMYS G. BDKSAKIUS. 225 
excepting the first one, are longer than their respective digits ; they are much 
compressed, single-edged underneath, curved, and acute. Their tips are reg 
ularly graduated, in position with decreasing disparity from 3d to 1st ; 3d-4th 
2d-5th-lst; the 3d being much the largest, the 1st a mere stump. The 
back of the hand is clothed with rather bristly hairs, which fall as a fringe 
over the sides of the hand, and of Ihe individual digits as well. 
As usual in cases of excessive growths of any kind, these great claws 
oi the hand vary a good deal in size and shape, according to the age and vigor 
of the animal in other words, according to the degree of use to which they 
are put. The hind foot is not remarkable, having an ordinary murine charac 
ter. The sole is perfectly naked, like the palm, and devoid of special pads or 
tubercles ; the skin being everywhere smooth. The toes are short ; the claws 
still shorter, weak, excavated underneath (like a badger's), little curved, and 
rather acute. The 3d is longest; then come 2d-4th-lst-5th ; the digit 
of the latter being a mere stump, and that of the 1st too short to carry the 
tip of its claw opposite the base of the 4th. 
The tail has an unfinished, or rather neglected, appearance, as if it were 
of no particular use. It is remarkable, however, for appearing to spring from 
a peculiar conical backward prolongation of rump, so that it is difficult to 
determine its true base. This enlarged basal portion is clothed like the rest 
of the body. From its apex, the tail continues with a shorter and more scanty 
furring. The tail is rather thick (in comparison with allied rodents) and 
somewhat quadrangular, the flattening of the under side being especially 
noticeable ; it tapers gradually to an obtuse tip. It is perhaps rather unu 
sually variable in length, averaging in its scant-haired portion about one-third 
of the length of head and body. 
The conical prolongation of the body above mentioned is that portion 
which protrudes beyond the ischia, which may be plainly felt on either side ; 
and on its under side appear the orifices of the digestive and genito-urinary 
systems, in close juxtaposition, and both directly at the base of the tail 
proper. In the rutting-season, however, the topography of the parts is 
changed, owing to the great distention of the perineum from the turgid 
organs within. In the female, there are three pairs of teats two inguinal, 
near together along the inside of the thighs ; and another pair, pectoral, at a 
29 COL 
