426 DR. J. MURIE ON THE ANATOMY OF THE WALRUS. 
The measurement of our Walrus’s hind foot yielded the following results :— 
inches. 
From the os calcis (at the point to which the caudal flap of skin reaches) 
in a straight line along the sole of the foot to the tip of the fifth 
digit, which is the largest in size. . . ; an inhetic: ofc les 
The same measurement carried to the distal Sid of erect fOGs\: osm cat ae LOR 
From the knee-joint to the tip of the fifth digit . . . . . . . . 26% 
The free part of the pelvic limb, ina straightline . . . . . . . I%% 
Girth at the proximal end or round the os calcis . . . . ia holds 
Extreme breadth at termination of digits when these are <cduteably 
distendedsi-i_ 2 Gh as , Pe arr at re el 
Diameter of same when eels aired and overlapping . .. . O$ 
Diameter of limb at the proximal end of the carpal bones . . . . . 4 
In Otaria the free part of the pelvic extremity is coequal with the above. The girth 
at the proximal end of the calcaneum is in favour of the young Morse. 
III. Dentition AnD Cayity or THE Mourn. 
1. The Teeth—My remarks on the teeth may be brief; for on this subject a host 
of writers! with more experience and greater opportunities of observation than myself 
have discussed in detail the immature and adult dentition of the Walrus, both as 
regards their numbers and homologies. 
The entire set of teeth in both jaws numbered twenty-four, viz. fourteen superiorly, and 
ten inferiorly (see figs. 6 & 7, Pl. LII.). Each upper canine protruded 1$ inch beyond 
the gum, was inclined rape and gently backwards, and had an antero-posterior 
diameter at the root of 6 inch. Ordinarily they were well nigh hidden by the lips; 
but as shown in fig. 3, chin view, they peered forth from the angle of the mouth 
surrounded by a partial erection of the labial mucous membrane. These canines, as 
previous observers have noted, were situated outside the more regular dental arch. 
The latter consisted of six teeth on either side, placed at subequal distances from each 
other; the anterior and posterior pairs were mere denticles, the rest of very moderate 
dimensions. In the mandible no symphysial teeth were visible; and of the five ramal 
teeth on each moiety the hindermost and penultimate were little more than tubercles. 
2. Palate—This is boat-shaped, and deeply concave both antero-posteriorly and 
transversely ; but especially is this the case in its anterior half or thereabouts. The 
length from the mesial or anterior incisive denticles backwards to the fauces is 
5 inches, and the greatest breadth is close upon 2 inches. The anterior palatine 
foramen pierces the tissues opposite the second large molar tooth. The mucous 
membrane, with its periosteal substratum lining the roof of the mouth, is very 
1 Retzius, the Cuyiers, Rapp, Deslongchamps, Wiegmann, Stannius, Owen, Jaeger, Gray, De Blainville, 
Peters, Husley, Gervais, Flower, and others, 
