MOLLUSCA. 27 



to the different forms of the shell, is unquestionably the most 

 obvious and the most ancient method. It was first employed 

 by Aristotle, the father of natural history, and even in the 

 present day its admirers are warm in its praise. It is with 

 great propriety termed the artificial method, because the 

 characters employed have but a remote relation to the more 

 important functions of the animal. This eminent philoso- 

 pher had the merit of forming the great divisions of unival- 

 ves and bivalves. He likewise separated the turbinated uni- 

 valves from such as have but an imperfect spire, and formed 

 many genera, or rather families, still retaining the names 

 which he imposed. 



The progress of the study of the shelly mollusca (the 

 naked kinds being in a great measure neglected,) made very 

 little progress for many ages after Aristotle had published 

 his method of arrangement. Indeed, the first work of this 

 sort which claims attention, is the Dictionarium Ostracolo- 

 gicum of Major, which was published in 1675. To him we 

 are indebted for the threefold division of shells into uni- 

 valves, bivalves, and multivalves, and for an explanation of 

 the terms then employed by conchologists. 



In the same career, but with more brilliant success, Lan- 

 gius followed, and, in 1722, published his Methodus Nova 

 Testacea Marina in suas Classes, Genera et Species distri- 

 buendi. The following character is given of this work by 

 the intelligent and industrious authors of the Historical Ac- 

 count of Testaceological Writers. (Linn. Trans, vol. vii. 

 p. 156.) " After having noticed a multitude of mere de- 

 scribers, we now come to an author who is not undeserving 

 of the title of a scientific one, and whose system, so far as 

 marine testacea are concerned, (and of these alone he treats) 

 certainly glances at the great clue to simplicity, which was 



