1 4 ELEMENTAR Y ANA TO MY. [LESS. 



in the whole of the Invertebrata (as far as yet known), with 

 the doubtful exception of Ascidians. 



Visceral clefts and arches may persist throughout life, as in 

 fishes ; but with respect to this, much more will be said later. 



From the foregoing concise statement of the more im- 

 portant general characters of man's anatomy and that of 

 animals generally, it is evident that his frame has been con- 

 structed upon a certain plan which in its main characters is 

 common to all the members of one large group (sub-kingdom) 

 of animals. 



This will become manifest when we proceed more into 

 detail and discover structures the utility of which is, to say 

 the least, apparently subordinate to their significance as 

 conforming to a general type of structure. 



21. It may well be the case that the rational faculties of 

 man could have been united to no more suitable a body than 

 that Avhich he possesses. Fancy may nevertheless amuse 

 itself by considering possibilities of structure (as shown by 

 what we find in existing animals) were he not tied down to 

 conformity to the vertebrate type. 



The fabled Briareus is suggested by the "thousand-legs" 

 and centipede. A natural armour, moved by a cunningly 

 adjusted internal mechanism, is suggested by the lobster. A 

 spear tipped with poison, like the wourari, is suggested by 

 the wasp ; and the appliances of even the most modern 

 warfare by the Bombardier Beetle. 



Eyes multitudinous, attached to movable stalks or at bur 

 fingers' ends ears in our breast, or attached to our shin- 

 bones are suggested by what we know of some insects. 



22. It is the fact, however, that man's body is strictly verte- 

 brate, and vertebrate only. It remains then to consider it 

 from the vertebrate point of view. His resemblances to all 

 animals below the Vertebrata are so general and remote, 

 that it would be profitless henceforth to consider and com- 

 pare (in going into the details of his structure) any such 

 distant resemblances or relationships as those presented by 

 invertebrate animals, of which we accordingly here take leave. 



It is needful, however, to hive a clear general conception 

 of the animals which compose the Vertebrate sub-kingdom, to 

 which repeated references will henceforth be made. 



23. The Vertebrata are divisible into five great classes, 

 which stand in different degrees of relationship one to 

 another: I. MAMMALIA (Man and Beasts); II. AYES 



