134 Animal Morphology. 



vertebrata should present themselves under a great variety 

 of forms and sizes, which no longer need a distinct 

 bony region. This bony mechanism is the proper cervical 

 region ; and the shoulder girdle is here, but a supplement 

 to the back of the head ; and flanking between the shoulder 

 girdle and the maxillaries are the small bones of the ear in 

 man and mammalia, enlarged to an enormous size, as a 

 kind of outside hoarding, to aid, with the shoulder girdle, in 

 protecting the heart and gills in their newly-acquired position 

 and function outside the ribs ; because the sense of smell in 

 water is useless ; to which all other parts are adapted, as the 

 absence of feet and legs, for without a neck the others would 

 be useless. 



In such a brief outline it is impossible to go further than 

 indicate the effect of removal of a tripartite apparatus in 

 altering the whole phase of sequences. Neither can it be 

 said that such phenomena as neckless vertebrata are a 

 necessity from the medium in which they live, and the 

 velocity with which they have to move, either for food or 

 for safety. For though their own condition is necessarily 

 a water one, yet we have tenants of the deep, and tenants 

 of the rivers and lakes, which run from fish to reptiles of 

 varied size and form, and even to mammalia themselves, 

 which, though beautifully metamorphosed and differentiated 

 so as to be adapted to the element in which they mostly, 

 and some entirely, live yet they possess some kind of a 

 cervical region, and with it some abortive attempt to deve- 

 lop the sense of smell. But in most birds and insects a 

 modified trachea and air cavities and vessels are used as an 

 apparatus for the Telluric sense, which is a complementary 

 sense to that of the sense of smell. 



We will now leave the subject of the senses to shortly 

 refer to that organ, the centre of all the senses, and the 

 source from which all active animal motions tend, or 



