143 



13 not to be trusted ; and that it is only by a multitude of specimens, 

 perfect as regards maturity and possession of opercula, that truth can 

 be arrived at, and species determined. 



The difficulty with Adams, as with myself, has hitherto been the 

 want of the original types of the fundamentai shells, so to speak. I 

 allude especially to the types of C. corrugatus, Sow. ; C subriigosus, 

 Sow. ; C. Jamaicensis, Chemn, ; and C. asperulus, Sow. [Of C. 

 suturalis there never was a doubt.] That difficulty is evidenced by 

 his note of interrogation "?" at p. 143, {id.) after " 1 C. corru- 

 gatus," and his description of "No. 1, C. corrugatus" below, 

 which mostclearly refers to a species, which to my certain knowledge 

 he has distributed indiscriminately as C. corrugatus and C.jugosus. 

 So he made up the collection which some time ago I presented to the 

 British Museum. I know that the presence or absence of the um- 

 biUcal keel was a guide he was always looking for. He did not seem 

 to understand Sowerby's description "umbilico magno, crenulato, 

 intus transyersim striato." Fid. Cont. Conch., p. 143. And beyond 

 a doubt, his description of the operculum of C. corrugatus at p. 143, 

 id. cannot for a moment be reconciled with Pfeiffer's in Cat. Pha- 

 neropneumona, p. 13. 



Mr. Cuming's liberaHty in lending his choicest specimens for 

 Science' sake is too well known to require my commendation. To 

 him I am now indebted for the loan of his types of C. corrugatus, 

 C.jugosus, C. subrugosus, C. Jamaicensis, C. seminudus, C. variam, 

 C. crassus, and C. asperulus, all of •which have passed through 

 Pfeiffer's hands : and I have examined those in the British Museum, 



C. asperulus is not in my collection, though amongst those I am 

 about to propose as new species, some approach very near to it. 

 The two specimens (one with part of the operculum) in the Cumin- 

 gian Museum, and those in the British Museum are somewhat likę in 

 character to Jamaica shells, especially C. crassus, in regard to absence 

 of umbilical keel, and C. rudis-planusąue (after mentioned) as regards 

 operculum ; and I do not wish to cast a doubt as to its habitat being 

 Jamaica, though I have not fallen in with it. 



Pfeiffer, in Cat. Phan. p. 1 3, has indicated that C. corrugatus was in 

 the British Museum when he wrote ; but unfortunately the specimens 

 there under that name vary so much in their opercula, that it is im- 

 possible to say to which he referred. In fact, his description is beUeved 

 to have been taken from one in the Cumingian Museum. But there 

 agaiu, equal doubts and uncertainty exist. Some shells, all named 

 by Pfeiffer, having opercula of the character of those of C. Jamaicensis, 

 are marked " C. corrugatus," and others are similarly marked with the 

 addition of " var.," the opercula of which answer his description in 

 Cat. Phan., p. 13, and have the precise character of that which it is 

 my intention to adopt as the true C. corrugatus, those characters 

 being totally dissimilar. Thence an interminable confusion esists, 

 which it is very difficult to disentangle. 



It seems to me that Sowerby and Pfeiffer have had only single 

 specimens to deal with, and not knovdng how many forms of oper- 

 cula there are, have certainly not been very minute in their descrip- 



