PURPURA. 



TESTA ovata vel oblonga, crassa, spira plerum- 

 quebrevi, nonnunquam subelongata; superficie 

 externa plerumque sulcata, granosa, tubercu- 

 losa aut spinoso-muricata; apertura plerumque 

 magna, ovata, subexpansa, labio externo ple- 

 rumque crenato, marglne acuto, intus dentato; 

 antice emarginato, canali brevi : columella 

 planulata; operculo corneo, nucleo laterali, 

 margine columellari tenuiore. 



ea 



The latest author who has written upon the Purpurse is 

 Duclos. It appears that he has ascertained from actual 

 examination that many true Purpurae are mixed up with 

 the species of the Genus Buccinum and other genera by 

 Lamarck in his Hist. Nat. des Anim. sans vertebres, and 

 Duclos, uniting all these together, has described ibi) 

 species which he considers as true Purpur?e, combining 

 them under six sections ot the Genus.* The great simi- 

 larity of those animals which he has had the opportunity 

 of examining, and the exact resemblance of the opercula 

 of numerous species has induced him to unite together 

 some of which Lamarck had formed a distinct Genus, 

 such for instance as Concholepas ; some for which Lamarck 

 had found a place with his I ritons, such as Ir. undosus, 



* Messrs Quoy and Gaimard appear since to have adopted the views of M. 

 Duclos, for they also refer Buccinum undosum, Linn to Purpura, ^nd denying 

 the right of Lamarck's Ricinulae to be dignified as a Genus, unite all its species 

 to Purpura. 



