On the distinctive characters of Cyfrma reticulata of Marly n, and 

 Cyprasa histrio of Meuschen. By John H. Redfield. Read 

 June 7th, 1847. 



Probably in no genus of mollusks, are the species better known 

 and defined, than in the genus Cypraca, for in none are the specific 

 characters more constant and unerring, while the labors of Euro- 

 pean conchologists within the last twenty-five years havo so greatly 

 extended the list of species, that there is perhaps less room here 

 for the discovery of new forms, than in any other family. 



While this is true in the main, it is also certain that there are some 

 species of Cypraea, which, though long known to naturalists, are yet 

 involved in some uncertainty, and of which it is hard to decide, 

 whether they should be regarded as distinct, or as mere varieties 

 of a common specific type, so doubtfully close are their affinities. 

 It is my aim in this paper to show the distinction between two 

 shells of this genus, which are still confounded by European 

 authors, even in the latest monographs, though the labors of our 

 early and lamented associate, Mr. Barnes, have led most American 

 conchologists to avoid the error. I refer to the Cypraia reticulata 

 of Martyn, and the C. histrio of Meuschen. Let us examine the 

 historic record of these species, and trace their synonomy. 



The earliest figures referrible to either of these species, are those 

 of Bonanni, 1681, Lister, 16S8, Rumphius, 1711, Petiver, 1713, 

 and Knorr, 17CC. These figures are usually quoted indiscrimi- 

 nately for C. histrio and C. reticulata, and from circumstpnces 

 connected with their date, it is probable they all represent the same 

 species; but with the exception of Lister and Knorr, they are so 

 rudely executed, that it is impossible to decide whether they belong 

 to the histrio of Meuschen, or the reticulata of Martyn. The figures 

 of Lister and Knorr, are tolerable representations of what I view 

 to be the true C. histrio. 



In 1784, appeared Martyn's Universal Conchology, where we 



