THE SEALS 



(PINNIPEDIA). 



Aquatic carnivores with feet converted into flippers, spindle shaped body, complete dentition, and 



zonary placenta. 



The Flipper-footed animals, or Seals, as 

 they are usually called, are carnivores adapted 

 to an aquatic mode of life. They show, in 

 fact, in all the features of their structure, with 

 the exception of the characters necessarily 

 following from this adaptation, a real affinity 

 to the true Carnivora, with which many 

 authors have united them as a sub-order. 

 They are, in relation to the Carnivora, what 

 the Chiroptera are to the Insectivora a 

 transformation of the general type with 

 reference to a quite specialized mode of life. 



The head is small, the muzzle seldom 

 prolonged, usually blunt, and the mouth 

 surrounded by very thick fleshy lips, on which 

 are set strong, stiff, and mostly spirally 

 twisted whiskers. The nostrils are in the form 

 of narrow slits at the point of the snout ; and 

 the cartilages by which they are surrounded 

 are so constructed that they close the open- 

 ings by their elasticity, while they can be 

 expanded by means of strong counteracting 

 muscles. These slits lead into wide nasal 

 cavities with labyrinthine olfactory chambers, 

 which are not less highly developed than in 

 the dogs, and, accordingly, bear witness to a 

 very keen scent. The large expressive and 

 beautifully coloured eyes are highly convex 

 in front, and are protected by broad eyelids 

 with very long lashes. The skull proper is 



round and broad, but the ridges by which 

 that of the land carnivores are marked are 

 slightly developed except in the eared seals 

 (Otarida). The outer ears are either entirely 

 absent or are only indicated by the weak and 

 very slightly projecting margins of the ear- 

 flaps. The mouths of the ear-passages can 

 be closed like the nostrils when the animals 

 dive. The neck is generally short, but well 

 marked off from the head. The form of the 

 body is that of a spindle, thick in front but 

 thinning towards the posterior extremity. 

 The body ends in a short flattened tail almost 

 hidden by the hind-flippers, which are always 

 directed backwards in an almost vertical 

 position, and form along with the tail a 

 powerful swimming apparatus. 



The limbs, although formed on the general 

 plan, yet exhibit marked peculiarities. The 

 bones of the fore-limb, with the exception of 

 those of the digits, are very short, twisted and 

 flattened, and in the ordinary seals are almost 

 wholly concealed by the strong muscles that 

 move them in the mass of the body. The 

 flippers show in the skeleton, indeed, the five 

 quite separate and pretty long digits, but in 

 the living animal they are united by strong 

 ligaments down to the last phalanges, which 

 are usually armed with not very sharp claws. 

 The hind-limbs are attached to a strong pelvis 



