IV PREFACE. 



and those new observations in their turn, to 

 carry to perfection the general principles of 

 distribution. In fine, to produce from this ac- 

 tion and re-action of the two sciences, such a 

 system of zoology, as might serve for an intro- 

 duction and a guide in anatomical researches, 

 and such a body of anatomy as might tend to 

 develop and explain the zoological system. 



" I by no means, however, intended to carry 

 this twofold labour into all the classes of the 

 animal kingdom ; the vertebrated animals natu- 

 rally claimed a larger portion of my attention 

 in consequence of their superior interest in every 

 point of view. Among the invertebrated tribes, 

 I have occupied myself more especially with 

 the naked mollusca and the larger zoophytes. 

 But the innumerable variations of shells and 

 corals, the microscopic animals, and the other 

 families which play no very apparent part on 

 the theatre of life, or whose organization af- 

 fords few facilities to the scalpel, did not require 

 to be treated with similar minuteness of detail. 



" It formed no part of my design to arrange 

 the animated tribes according to gradations of 

 relative superiority, nor do I conceive such a 

 plan to be practicable. I do not believe that 

 the mammalia and birds placed last, are the 

 most imperfect of their class ; still less do I 



