698 CLASS xvii. 



towards each other, in others turned outwards. Profc N. C. DE FREMERY 

 was of opinion, that on this and other accounts two species should be 

 adopted. SUNDEVALL, however, justly observes that scarcely two skulls 

 can be examined in which no minute differences in the direction and size of 

 the tusks can be observed; Aorsbercettelser for 1837 1840, p. in. See also 

 STANNIUS Ueber Gebiss und Schddeldes Walross u. s. w. MUELLER'S Archiv 

 f. Anat. u. Physiol. 1842, s. 390413. 



Phalanx II. (Phocina). Incisor teeth persistent, upper canines 



included, molars -= = or - = ^ars non e or small. Two or 

 o o o o 



four mammae, ventral, placed near the umbilicus. 



The seals (the genus Phoca L.) live in various seas, and also occur, 

 at least in part, at the mouths of rivers ; they are especially nume- 

 rous in the polar regions, and are wanting in the tropical parts of 

 the ocean. The structure of the body is adapted exclusively for 

 rapid and sustained swimming. The seals creep upon the shore, 

 and then bend their spine in direct curves up and down, which 

 motions have been compared with those of the surveyor caterpillars. 

 They delight in lying on the shore and on rocks in the sea to sun 

 themselves. They live upon molluscs, crustaceans, &c., but princi- 

 pally upon fish. Their note is a bark, not so strong as that of dogs, 

 and which they make heard at evening time especially, and on 

 approaching change of weather. Their body is covered with harsh 

 hair that lies close to the body ; the skin secretes a fatty matter by 

 which the hair is rendered more glossy, and the body more effec- 

 tually protected from the water; below the skin a thick layer of 

 fat is disposed over the whole body, whilst on the other hand fat 

 is almost entirely absent in the inward parts. We have already 

 remarked above upon some peculiarities of their internal structure; 

 amongst which is the length of the intestinal canal (p. 582), the 

 large sinus of the vena cava (p. 586), &c. They have no clavicles, 

 a very small humerus and femur, fifteen ribs, five lumbar vertebrae. 

 The brain is very large. The organ of smell appears to be pecu- 

 liarly developed, whilst the inferior turbinated bones have many 

 plates, and afford a large surface for the mucous membrane. The 

 tongue is rough and bifid at the extremity. Long whiskers, 

 attached to the lips, conduct the impressions of touch to branches 

 of the fifth pair. These hairs are thick and flat, and have in most 

 of the species sinuous margins, which give them the appearance of 

 being knotted or jointed. (See ALBINI Annot. Acad. in. Tab. vi. 



