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LETTER VII. 



AN EXPOSITION OF CUVIER's ARRANGEMENT OF MOLLUS- 

 COUS ANIMALS. 



I have already mentioned that Cuvier was the first who 

 grouped together the animals to which the name of Mollus- 

 cous is now properly restricted. Previous to the publication 

 of his memoir on the classification of avertebrate animals in 

 the year 1795, the Mollusca were intermingled with worms 

 and with zoophytes, while a great number of them stood 

 detached from their allies under the ordinal designation Tes- 

 tacea, merely because they were enclosed in hard calcareous 

 shells, — the knowledge of the inferior tribes being then too 

 little advanced to admit of the application of any characters 

 but those that were derived from exterior form and consist- 

 ence. By his numerous careful dissections, Cuvier was 

 early enabled to detect and appreciate the unnaturalness of 

 the prevalent systems ; and when his labours had convinced 

 him that their overthrow was necessary to the progress of 

 science, they had at the same time furnished him with the 

 materials out of which he sought to erect a new system, 

 which has been of incalculable advantage to scientific con- 

 chology, and which remains untouched in all its grand linea- 

 ments, though his successors have certainly improved and 

 worked out many of the minor details. These we shall 

 have a future opportunity of discussing. I mean at present 

 to give you an outline of the original as it came from its 

 author's last revision, without note or comment ; and when 

 you are made aware that this great naturalist continued to 

 regard it as one of the principal works on which his fame 

 might safely rest, and watched it with a degree of parental 

 jealousy, unwilling that the parentage should be either 

 doubted or divided, you can have no need of being urged 

 to make yourself its master. " It is well known," Cuvier 

 himself tells us, * " how much care and time I have de- 

 voted to the anatomy of the mollusca in general, and in 

 particular to the knowledge of the naked mollusca. The 

 determination of the class, its principal divisions and sub- 

 divisions, all repose upon my proper observations; for the 



* Regne Animal, torn. i. picf. xxvi. Paris, 1829. 



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