PREFACE. IX 



conceive, with more precision, the functions of 

 certain organs. I have attempted to fix deter- 

 minately, the animals to which the various con- 

 figurations of shells belong, and to range the 

 latter accordingly. In the ulterior divisions of 

 shells, whose inhabitants mutually resemble, I 

 have chiefly confined myself to a brief sketch 

 of such as are admitted by MM. Lamarck and 

 Montfort. Those few genera and sub-genera 

 which belong to myself, are the result of obser- 

 vation. In this department, however, I do not 

 profess to have observed a similar degree of 

 critical accuracy, as on the vertebrated animals 

 and the naked mollusca. 



" The establishment of the annelides as an 

 order, I believe, I may justly claim for myself, 

 although the invention of the name does not 

 appertain to me. I have extricated them from 

 the state of confusion, in which they had been 

 left by former naturalists among the mollusca, 

 the testacea, and the zoophy es ; given them a 

 more natural arrangement, and thrown con- 

 siderable light on their several genera, by the 

 fixed definitions I have made on the subject in 

 the Dictionary of the natural Sciences and 

 elsewhere. 



"The Crustacea, Arachnoides, and Insects 

 belong (with the exception of some anatomical 



Vol. i. c 



