ioo COMPARATIVE ANATOMY AND PHYSIOLOGY. 



By the almost universal consent of zoologists, the 

 highest " order " of the Mammalia is that of the 

 Primates ; of these, the lowest suborder is that of 

 the L*emuroidea (of which some naturalists would 

 make a separate order), the highest that of the 

 Anthropoidea, which is divisible into five " fami- 

 lies," the highest of which is the Homiiiidse, 

 represented by the single genus Homo. 



While Man is said to be the highest of animals, 

 it is not to be forgotten that in the other divisions 

 of zoologists there are forms in which structural 

 characters are at least as perfectly elaborated, when 

 we bear in mind their ancestral history and the 

 relation of structure to function. The horse, the 

 whalebone whale, the woodpecker, or the boa con- 

 strictor, are, to cite only a few examples, forms in 

 which structural organisation is as, if not more, com- 

 plete, and as differentiated as it is in man. 



There remain to be considered very briefly several 

 groups of animals which, in the present state of our 



knowledge, cannot be 

 satisfactorily placed 

 with any of the great 

 phyla which we have 

 just been describing. 

 Of these the more im- 

 portant are : 



1. Brachiopoda. 

 -These were placed 

 by earlier naturalists 

 with the Mollusca, from 



"Fig. 49. Crania anomala. b, Arms. i i i j_-u 



(After Davidson.) which, however, they 



are to be distinguished 



in consequence of the segmentation of the larva, the 

 dorsal and ventral positions occupied by the two 



