134 
CARNIVORES. 
behind. Dr. Murie has, however, ascertained that in the case of the Greenland and 
crested seals there is a kind of motion somewhat intermediate between the above 
and that characteristic of the eared seals. Thus the former of these two species 
“ very often uses its fore-limbs, placing these on the ground in a semi-grasping 
manner, and, by an alternate use of them, drags its body along. The hind-legs 
meantime are either trailed behind slightly apart, or with opposed plantar surfaces 
slightly raised and shot stiffly behind. On uneven ground, or in attempting to 
climb, a peculiar lateral wriggling motion is made; and at such times, beside alter¬ 
nate palmar action, the body and the hind-limbs describe a sinuous spiral track.” 
On the other hand, the common seal appears far less capable of making use of its 
fore-limbs in progression on land, these being only occasionally employed to obtain 
a hold on rocks. 
On smooth ice seals are able to progress with considerable rapidity; the 
average rate being about one mile an hour in cool weather. Such journeys are 
always undertaken during the night; and the seals advance by raising their bodies 
from the ice by means of the fore-limbs, and then drawing themselves forward. 
On land, seals will occasionally travel considerable distances; and it is on record 
that in the winter of 1829 a grey seal in Norway travelled through the snow a 
distance of fully thirty miles; the time occupied in accomplishing this journey 
being believed to have been about a week, during which period the creature could 
not have touched food. 
The true seals are not a very ancient group, geologically speaking, although 
their remains are found through the Pleistocene and Pliocene strata, and in a portion 
of those belonging to the Miocene period. Fossil seals are very common in the 
Pliocene deposits of Belgium ; most of them being more or less nearly allied to the 
species now inhabiting the Northern Hemisphere. It is very noteworthy that while 
true seals range downwards to the Miocene period, no remains which can be 
definitely assigned to the eared seals have hitherto been discovered in any but the 
most recent and superficial deposits. If this apparently late origin of the eared 
seals be confirmed by future researches, it will go far to confirm the suggestion 
that the latter have taken rise from land Carnivores quite independently of the 
true seals. 
The Grey Seal. 
Genus Halichcerus. 
The grey seal (Halichoerus grypus), which is the sole representative of its 
genus, belongs to a group confined to the Northern Hemisphere, and distinguished 
from all the other members of the family by the presence of three pairs of incisor 
teeth in the upper jaw, and two pairs in the lower jaw. A further characteristic 
of the group is to be found in the presence of claws on all the toes of both pairs of 
limbs; while all those of the hind-feet are of nearly equal length. 
The grey seal is at once distinguished from the other members of this group by 
the circumstance that the crowns of the relatively large cheek-teeth are composed 
of but a single conical cusp, although there may occasionally be fore-and-aft cusps 
in the last two teeth of the lower jaw. Another peculiar feature of these teeth is 
