340 MANATEE, ZEUGLODON. OVO- VIVIPAROUS MAMMALIA. 



mouths of the rivers opening on the north and north-east of South 

 America, and the coast of Mexico ; it measures six or seven feet 

 in length ; and its paddles exhibit rudiments of nails, by the aid 

 of which the animal sometimes drags its unwieldly body on shore, 

 and crawls up the banks, either to bask in the sun, or to seek 

 for terrestrial vegetables. Another species is found on the 

 western coast of Africa ; and a third along the shores of some 

 parts of North America. Some fossil teeth have been discovered 

 in America, which are regarded by Professor Owen as having 

 belonged to an animal of this family, to which he has given the 

 name of Zeuglodon. This name, which means yoked-toothed, 

 was suggested by their distinguishing peculiarity, the form of 

 the posterior molars, which resemble two teeth tied or yoked 

 together. 



SUB-CLASS II. OVO-VIVIPAROUS MAMMALIA. 



306. The general character by which the animals of this divi- 

 sion are distinguished from the true Mammalia have been already 

 explained ( 118); and it has been shown that these are of suffi- 

 cient importance, to require that the several species which agree 

 in it, should be associated together in a separate group ; even 

 although they differ considerably from one another, in the nature 

 of their food, and in the conformation of those organs by which 

 it is obtained and digested. Thus we find, in some members of 

 this sub-class, an opposable thumb, as perfect as that of many 

 Quadrumana ; in others, a set of teeth and sharp claws, obviously 

 adapted to a Carnivorous regimen ; in others, again, the general 

 organisation of the Insectivora ; in others, an approach to the 

 peculiar conformation of the Rodentia; and in others, the com- 

 plete absence of teeth, which characterises the true Edentata. 

 Hence some Naturalists have been disposed to arrange these 

 several animals under the Orders, to which they would be referred 

 by the characters just adverted to ; forgetting that they are 

 distinguished from these by characters of far higher importance, 

 those relating to the structure of the brain ; which correspond, 



