SEALS. 233 



CARNI VORA . PINNIPEDIA. 



Sub-Order CARNIVORA PINNIPEDIA. 



Seals. 



There are few groups among the whole of the main- 

 miferous class which are so indistinctly known, or of 

 which the species are so often confounded, as the Seals 

 and their allies. The great general similarity of their 

 form and habits has occasioned the confusion of distinct 

 species under one name, while, on the other hand, their 

 great variation in colour and markings, whether acci- 

 dental or connected with differences of age or sex, has 

 often led to the enumeration of species which do not 

 exist in reality. Under these circumstances, it is 

 evident that structural differences alone can be depended 

 on in the discrimination of these animals, and the 

 characters of the skull and of the teeth will generally 

 be found most available for this purpose, aided by the 

 outward proportions and other circumstances. The 

 characters of the northern Seals have been greatly 

 elucidated by the labours of De Blainville, of George 

 and Frederick Cuvier, and of Lilljeborg, Nilsson, and 

 Gray, but comparatively little has been done since the 

 publication of our first edition in the determination of 

 the species which occur on the British coasts, and con- 

 siderable uncertainty still remains to be cleared up by 

 future observers. 



The true Seals, or Phocidw, along with the Walrus 

 (Trichecus) and Eared Seals [Otaridm) constitute a very 



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