and the Elements in which they live, 177 



factorily settled. But there are families in which we can already 

 see our way and arrive at precise conclusions. Among Carni- 

 vorous Mammalia we have three very distinct types : the Pinni- 

 poda or Seals ; the Plantigrada or Bears ; and the Digitigrada, 

 Dogs and Cats. Now even if objections were raised against the 

 association of the Walrus with the common Seals, there can be 

 no doubt of the inferiority of the latter when contrasted with 

 Plantigrada and Digitigrada. Their short fin-hke legs, their 

 clumsy body in connection with their aquatic marine life, assign 

 them a lower position, and the Plantigrada must be considered 

 as intermediate between them and the Digitigrada. Now among 

 Digitigrades, even if we take isolated genera, we are led to assign 

 to the species with aquatic habits an inferior position among their 

 nearest relatives. The Polar Bear comes decidedly nearer the 

 Seals in all its habits than any other species of that genus, and 

 on that ground should be considered as inferior to the terrestrial 

 species. Again, the others, with their palmate fingers, rank 

 lower than their terrestrial relatives : and we may even find that 

 such considerations will hold good among the varieties of one and 

 the same species; for we have varieties among the Digitigrade 

 Dogs in which the fingers are palmate, a character which is de- 

 rived from the imperfect development of their legs, preserving 

 throughout life their embryonic form ; and these varieties among 

 Dogs are the most playful and at the same time most aquatic in 

 their habits, preserving in their adult state chax'acters of the 

 young and habits of the lower types, — this playful disposition 

 being universal even among the most ferocious of the Cat tribe. 

 I shall abstain purposely from tracing these comparisons higher 

 up among Monkeys, and in the human families, from fear of al- 

 luding to exciting topics ; but leave it to the philosophic observer 

 to consider how far the idea of an aquatic Monkey is compatible 

 with the high position which these animals hold in the class of 

 Mammalia ; and how curious it is that in the human family there 

 are races which difi"er so much in their natural dispositions, mode 

 of life, habits, and adaptation to higher civilization ; and how 

 closely these natural dispositions are connected with apparently 

 insignificant peculiarities of structure. 



Upon reviewing the facts mentioned above, and the inferences 

 derived from the facts, no impartial observer can in future deny 

 the importance of the study of the natural relations between ani- 

 mals and the media in which they live ; and the close connection 

 which exists between them and the gradation of their structure. 

 But this being the case, it must be a matter of surprise that the 

 views so long entertained of the importance of this connection, 

 which led earlier naturalists, generally, to the classification of 

 animals accordmg to the media in which they live, should have 



