MOLLUSCA. 5 



sification corresponding to the animal organization. The system 

 of Linnaeus in this class was therefore unavoidably defective, as 

 every classification of animals must be, the basis of which is not 

 founded upon their anatomical structure. For many years, how- 

 ever, like the other arrangements of that great naturalist, it met 

 with almost universal assent, until the later investigations of nu- 

 merous observers led to a classification more conformable to na- 

 ture for this interesting but long neglected class of animals. 



Though the greater number of the naturalists of the last 

 century followed the system of Linnaeus, yet not a few of the 

 Continental Zoologists perceived the necessity of having re- 

 course to the animals in arranging this class. In 1743, Dau- 

 benton, in a memoir read to the Academic des Sciences, show- 

 ed that a knowledge of the animals was indispensable. In 

 1756, Guettard characterized a considerable number of ge- 

 nera by the examination of their structure. In 1 757, Adan- 

 son, in the only volume published of his voyage to Senegal, 

 treated at great length, not only of the characters presented 

 by the shell, but also of those furnished by the tentacula, 

 the eyes, the mouth, the respiratory aperture, and the foot. 

 Geoffrey, Muller, Fabricius, Forskal, and many others, conti- 

 nued to improve the science by general arrangements, and the 

 description of species. Pallas, in particular, asserted, that in 

 the general disposition of the animals of this and the following 

 class, the absence or presence of the shell is to be considered as 

 of inferior importance ; and Poli proposed a natural arrange- 

 ment, in the establishment of the orders and genera of which he 

 confined himself solely to the characters afforded by the animal. 

 It is not necessary here to detail the improvements made in 

 this department of science by the numerous naturalists who 

 have devoted their attention to the examination of molluscous 

 animals. Of general and particular works on the subject there 

 is indeed an overwhelming multiplicity ; for the ease with which 

 the calcareous spoils of the Mollusca are procured and pre- 

 served, the great beauty of many of them, and the frequency of 

 collections in all countries, have given rise to a host of writers. 

 The British naturalists have, for the most part, followed the 

 footsteps of Linnaeus ; but it is to the Continental writers that 

 science is indebted for almost all that is known of the organi- 

 zation of the Mollusca. Among these. the names of Cuvier, 



