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A List of the Genera of Recent Mollusca, their Synonyma 

 and Types. By J. E. Gray, Esq., F.R.S. etc. 



The generic names which have been used in Mollusca have 

 become so numerous that I have long thought it desirable that they 

 should be submitted to a rigid examination, for the purpose of re- 

 ducing those which are only synonyms of genera already esta- 

 blished ; and for the purpose of doing so with justice to previous 

 writers, it is necessary that attention should be paid to the dates of 

 their original publication, which have been too much neglected by 

 several writers in this branch of zoology. 



I have therefore sent to the Society the following list, which, 

 though I have paid great attention to the subject, I am aware is yet 

 very imperfect, as a commencement in what I consider the right di- 

 rection, and I hope that it may be the means of drawing the attention 

 of other students of this class of animals to the subject. 1 have been 

 induced to send it in its present state, as I am constantly requested 

 by both English and continental conchologists to supply them with 

 copies of the Synopsis of the British Museum for 1838, 1840, 1842, 

 and 1 844, which contains a list of the genera of Mollusca, and which 

 is now out of print, and also often to give them information with 

 regard to the authorities for the several genera contained in that 

 list, which shows that there is an evident want of some recent infor- 

 mation on this subject. 



It is needless for me now to dilate on the importance of attending 

 to the law of priority, which I have always advocated, for that is 

 now almost universally allowed ; yet I am quite prepared for hearing 

 several conchologists complain of the changes which the observance 

 of this just law will force them to make : thus Cyclostoma and Heli- 

 cina, instead of being applied to land-shells, must be the names of the 

 Delphinula and Rotella of Lamarck's ' Histoire' ; Terebellum that of 

 Turritella of the same author ; so that though these generic names 

 are still used, they will have a different signification to their present 

 one. Other names in very general use, as Oliva, &c, will have to be 

 erased from the system, for this genus was established and well- cha- 

 racterized under the name of Strephona, by Browne (along with several 

 other genera), between the publication of the tenth and twelfth 

 editions of Linnseus's ' Systema Naturae,' though it has been over- 

 looked by Lamarck and other authors. 



I may here observe that the change with respect to Cyclostoma and 

 Helicina is produced by Lamarck having used the same names with 

 very different significations in his ' Systeme ' and ' Histoire.' In the 

 latter of these works he has in one or two instances altered the names 

 which he had previously given to a genus ; and in like manner allowed 

 the names before used, such as Meretrix and Donacilla, to drop out 

 of the system, no notice being taken of the change or its cause. 



The method I have followed is to observe the first name given to 

 the genus and the type on which it was founded, and then to accu- 

 mulate the synonyma around the genus. Where a succeeding author 

 has referred to a different species as the type of the genus, I have 



