DR. J. MURIE ON THE ANATOMY OF THE WALRUS. 461 
Looking at the teeth as instruments of mastication, the greater triturating surface of 
the molars, as compared with the fish-eating Seal’s, is in concord with the molluscivorous 
habits of the Walrus. 
Little appreciable difference is exhibited throughout the Pinnigrades in the con- 
struction of the alimentary canal. It is simply that of a Carnivore, with, however, a 
moderate-sized cecum. The great glandular superficies and correlated large lymphatics 
point to means of speedy and frequent digestion; and in the Walrus these apparatus are 
extraordinarily developed. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
Fig. 
DESCRIPTION OF THE PLATES. 
PLATE LI. 
. Profile of the head and neck of the Society’s specimen of young male Walrus 
(1867), from a photograph taken immediately after death. Reduced to about 
two-thirds natural size. a.c. Placed in front of the external auditory canal ; 
a projecting pinna is wanting. 
PLATE LIL. 
. Foreshortened view of the muzzle and partially opened mouth, the upper lip 
being dragged upwards and outwards by hooks. When in this position, the 
labial bristles radiate, or are bent somewhat backwards. C. Upper canine of 
right side; the pointer rests on the distal boundary line of the thick layer of 
cement. /.l. Lower lip. Photographed natural size, and diminished to two- 
thirds in the present lithograph. 
. Under aspect of the chin, muzzle, and part of throat. th. Parallel skin-folds of 
throat. ch. Rough hairy chin. C. Left upper canine protruding at angle 
of mouth. 
. About two-thirds natural size, foreshortened view of muzzle, nares, and chin, 
the mouth and nostrils being closed. a.n. Anterior nares. J.J. Lower lip. 
The shadow of the beard beneath simulating an oral cavity. The bristles 
are seen to converge and overlap each other. From a photograph. 
. Sketch of the semidilated anterior nares, about natural dimensions. @.n points 
to the right orifice. 
. Reduced semidiagrammatic view of the palate and dentition of the upper jaw. 
. A similar sketch of the anterior segment of the mandible and teeth. 
