24 BULLETIN OF THE 



from liosmarus in the form of the skull, in the relative length of the 

 cervical vertebrae, in the form of the scapula?, and in general propor- 

 tions. In respect to the limbs, the principal difference consists in the 

 relatively greater shortness of the foot in the walrus as compared with 

 the other extremital segments (the femur and tibia posteriorly and the 

 humerus and radius anteriorly), and the great divergence of the digits 

 of the hind feet. 



A skeleton of an aged male Alaska walrus I find varies in length but 

 a few centimetres from that of an aged male of E. Stdleri. The dorsal 

 and lumbar vertebrae have the same length in both, but the cervical 

 vertebne in the walrus are considerably shorter, and the caudal some- 

 what longer, than they are in the other. A vast difference, however, 

 is seen in the general form, the E. Stdleri being slender and the walrus 

 exceedingly robust, the bulk of the body in the latter being nearly 

 twice that of the former. This gives a greater length to the ribs of the 

 walrus, and much larger centrums to its vertebrae ; but the develop- 

 ment of most of the vertebral apophyses is nearly the same in both. 

 The great thickness of the body also serves to increase the dispropor- 

 tionate shortness of the neck, as well as to increase the relative size of 

 the pelvis and the divergence of the ilia. The limbs also are hence 

 necessarily longer in proportion to the length of "the body. The feet, 

 however, are proportionally less developed than in the eared seals, and 

 the whole form of the body indicates an animal of slow movements, 

 especially in the water, and of rather sluggish habits. 



The scapula in the walrus is long and narrow, with its greatest 

 breadth near the middle, and its spine or crest situated but little behind 

 the median line. In Eumetopias the scapula is short and broad, with 

 its greatest breadth at the upper border, and its spine quite near the 

 posterior edge. These considerable differences seem to result neces- 

 sarily from the correlation of the form of the scapula with the great 

 depth of the body. 



The great differences which obtain in the skulls of these types, 

 through the enormous development of the canines in the walrus, are too 

 well known to require a detailed description. In the latter the skull is 

 exceedingly massive throughout, but is especially developed anteriorly, 

 to afford support to the immense tusks, while in Eumetopias it has the 

 normal carnivore form. 



The bones of the walrus, it may be added, are lighter and softer than 



