214 WHITNEYA, RAPA, MAGILUS. 



Genus WHITNEYA, Gabb. 



This fossil genus is said by its author to be related, probably, 

 to Fasciolaria, but I agree with Stoliczka that its nearest apparent 

 ally is Melapium ; from which I can only separate it geologically. 



WHITNEYA FicoiDES, Gabb. PI. 68, fig. 397. 



Cretaceous, Cidifornia. 

 Genus RAPA, Klein. 



This, like the preceding genus, has only one properly authen- 

 ticated species ; but that, is unquestionably very closely related 

 to LeptoconchuH. The operculum is of the normal purpuroid 

 type, but like the shell, very thin, translucent and yellowish 

 white. 



R. PAPYRACEA, Lam. PI. 67, figs. 393, 396, 392. 



Shell very thin, covered by variable revolving stride or ribs, 

 which, towards the base, become scabrous; sutures also scabrous. 

 White or light yellowish, frequently tinged with rose-pink 

 towards the base. Length, 1 •75-2- 75 inches. 



Indian Ocean, China, PMUppines. 



Being very thin, the shell of this species is peculiarly liable to 

 distortion. The Bulbus incurvus of Dunker (^fig. 396) I can only 

 regard as one of these variations of form. I give a copy of the 

 original figure of it. I copy below the description of another 

 species, which does not appear to possess good distinctive 

 characters. 



R. BULBIFORMIS, Sowb. 



Subglobose, spirally imbricately Urate below ; spire produced ; 

 Avhorls six, rounded ; aperture somewhat narrowly pyriform ; lip 



crenulate Ijelow. 



Tongatahoo, Friendly Isles. 

 Has a much more produced spire than the known species ; with 

 rounded whorls. I am not acquainted with it ; has not been 

 figured. May = E. papyracea. 



Genus MAGILUS, Montfoit. 



In the " Genera of Recent Mollusca," the authors, following 

 Ruppell, distinguish the species of Leptoconchus from the single 

 species of Magilus. They thus describe the animal of the former : 



The mantle margin is greatly thickened and fieshy ; the tenta- 



