﻿A. E. Verrill on the Mollusca of Europe and N. America. 5 



or difference of closely allied forms ; and no one can claim to 

 be infallible in such matters. Some of tlie errors to be men- 

 tioned do not, however, come under this head ; for the species 

 united have only remote affinities. Nevertheless the naturalist 

 who has collected and carefully studied animals in their native 

 haunts, under various circumstances, in many localities, and in 

 great numbers, has, other things being equal, a very great ad- 

 vantage in these matters ; and therefore I believe that Mr. Jeff- 

 reys would in most cases agree with me had he collected and 

 studied as many American shells as I have, during the past fif- 

 teen years, or if he were as familiar with them as he is with the 

 British species. In most of the cases to which I refer, my own 

 conclusions are in harmony with those of Dr. Stimpson, who 

 devoted so many years to collecting and carefully studying our 

 shells, and who is well known, for his accuracy in such matters. 

 And it would be strange indeed if all American naturalists as 

 well as many eminent foreign ones, have always been making 

 such ridiculous blunders in regard to some of our most familiar 

 shells as Mr. Jeffreys would have us believe. 



Thus he states (p. 240) that '' Gemma gemma''' (or Totteina 

 gemma) is the young of Venus Tuercenaria ! But it has long 

 been known to European as well as American conchologists 

 that the animal of gemma is very different from that of mercena- 

 ria, and quite peculiar ; that the hinge is constructed on a very 

 different type is well known ; and Prof G. H. Perkins has 

 shown (Proc. Bost. Soc. N. H., 1869, p. 148) that ^ew ma is vivi- 

 ■parous, producing about three dozen young, with .well-formed 

 shells, at one time. Moreover, the young shells of mercenaria^ 

 smaller than the adult ge7nm,a, are sufficiently abundant on our 

 shores, and may be seen in many American collections ; they 

 are certainly very unlike the gemma in form, sculpture, and 

 hinge, as has been well known for more than thirty years. 



Again, he states that Area transversa is a variety of Area, 

 pexata, the former being put down as northern, the latter as 

 southern. That these shells are widely different in form and in 

 the structure of the hinge is well known ; for Dr. J. E. Gray 

 many years ago established a new genus {Argina) for the latter, 

 on account of its very peculiar hinge. That the animals are 

 also quite different I can assert from personal observation. 

 Moreover, the differences in the hinge, epidermis, and form are 

 remarkably constant ; and, finally, the two species have the 

 same geographical range from Cape Cod to South Carolina, and 

 are often found together. Both are very common in Long 

 Island Sound and New Haven harbor ; and I have examined 

 hundreds of specimens of both species without finding the 

 slightest evidence in favor of Mr. Jeffreys's views. Indeed, they 

 are only distantly related, and evidently belong to distinct gen- 



