OP SOUTHERN INDIA. 85 



6. Fanopcea, Menard, 1807.* Shell nearly equivalve, large, oblong; hinge 

 with one strong tooth in each valye, pallial impression distinct, posteriorly deeply 

 insinuated, ligament supported by prominent fulcra ; — burrowing in sand. 



It is really difficult to point out a prominent distinction between Saxicava and 

 JPanopcBa, except that the latter generally are less inequilateral shells and of large 

 size ; and in proportion all the characters of Fanopcjea, as pallial sinus, hinge-teeth, 

 and the fulcra of the ligament, appear more distinctly marked ; their habitat is also 

 somewhat different. 



H. and A. Adams, in their work on the recent genera of MoUusca, correctly 

 distinguish between Glycimeris and Fanopcsa, but their application of the names 

 is based upon an incorrect interpretation and cannot, therefore, be retained. The 

 name FanopcBa was proposed by Menard for a tertiary species, which he calls 

 P. Faujasi, but which has been proved to be identical with the recent P. glycimeris 

 of Born, or P. Aldrovandi, Men., and this species H. and A. Adams refer to 

 Glycimeris, retaining the name FampcBa for P. norvegica of Spengler. Thus the 

 name Fanopcea evidently cannot be used for the Norwegian species, but when we 

 consider that Klein in his admirable "Tentamen" already refers to a Norwegian 

 species, which is probably the P. norvegica of authors, and, further, that Deshayes 

 described that species (in the 2nd edit, of the Anim. s. vert.) under the generic 

 name of Glycimeris, I am not certain whether it were not preferable to retain that 

 generic name for it instead of creating a new one. For I believe there is sufficient 

 reason for placing the Norwegian species in a new genus, which connects the true 

 FanopcBCB with Cyrtodaria, as I shall presently point out. 



7. Glycimeris, Klein, 1753, (Tent, meth., p. 170, Fanopcea apud H. and A. 

 Adams). Shell thick, nearly equilateral, hinge with one tooth in each valve, fitting 

 into a special cavity in the other valve; pallial line interrupted, moderately 

 insinuated, posterior muscular impression very elongated. 



In conformity with the few distinctions in the animals of Fanopcea and 

 Glycimeris fGL norvegica), pointed out by H. and A. Adams, those of the shells 

 are, I think, deserving of a special notice. The shell of GL norvegica is not only 



=* To prevent furtlier confusion I adopt here Menard's name Fanopcea. The recent species, which is the type 

 of the genus - P. Aldrovandi - has been, besides several others, well known to the oldest writers on conchology. 

 Klein in 1753 was the first who classed several of the species [the Norwegian one being evidently known to him] 

 under the generic denomination of Glycimeris. Klein gives a figure of one species and quotes next the CJiama 

 glycimeris of Aldrovandi, but having applied the name CJiama previously to another group of shells, Klein was 

 perfectly aware that a new generic name was required. Thus as far as the generic name is concerned, it was perfectly in 

 accordance with our present system of nomenclature. And, what notice did Klein's well selected name Glycimeris 

 receive from his successors ? Mr. Deshayes (in his 2nd edit, of the Paris fossils, p. 172,) tells us, that Lamarck, 

 struck with the peculiar characters of Born's My a glycimeris (==: Chama glycimeris, Aldrov.,) proposed in 1799 a 

 new genus Glycimeris ! A few years back Lamarck applied the name Glycimeris to a perfectly different shell, which 

 Daudin called Cyrtodaria. And, again, after a few years, when Menard proposed his name Fanopcea, Lamarck 

 dropped the name Glycimeris altogether. Whether Lamarck was, or was not, (which latter would be surprising) 

 acquainted with Klein's " Tentamen meth.," &c., it is clear that he was not the author of the genus Glycimeris, but this 

 name has been so unjustly treated and differently applied, that I do not for a moment see any benefit to science in intro- 

 ducing it again in a sense different from that generally adopted ; still when facts are to be given, it is just to former 

 labourers to give them in full. 



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