326 COOKE : ON THE GENUS PURPURA. 



say that the W. Indian form now generally known as undata 

 Lam. is 'equally common on the W. Coast of America.' The 

 W. Indian and W. American forms may have a common 

 origin, but at present they are completely distinct, and no one 

 who has given careful study to large series of specimens could 

 possibly confound them. Carpenter worked out the synonymy 

 and the distribution of the various forms in his Catalogue of 

 Mazatlan Shells (p. 477). Reeve, by figuring as Lamarck's 

 undata an undoubted specimen of biserialis Blainv. (the W. 

 coast form of haema stoma) ^ and C. B. Adams, by identifying 

 this same form (' Panama Shells,' pp. 80 — 81) with undata Lam. 

 have both contributed to the confusion and perhaps led Tryon 

 astray. 



Page 169. — P. haemastovia L. var. Blainvillei Desh. ' To 

 this form heXoug... F. /auelli Kien.' 

 F. Janelli Kien., is a Cantharus ! 



Page 178. — '■ F. mix 'R.e.&ve.=Murex Edwuidsi 'Psiyr.' 

 Such an astonishingly bad guess as this carries its own 

 refutation. 



Page 200. — ' Ciima piirpuroides D'Orb. (=C fusiformis 

 Blainv.). This well-known species... is said to have a fusoid 

 operculum, it will therefore be described and figured in Vol. 

 III. of this work.' 



Turning to Vol. III. p. 109, vi'e read : — 



' Melongeiia ftisiformis Blainv. This shell is apparently 

 very closely related to Cuma kiosqui/onin's, but the operculum, 



according to D'Orbigny, is not purpuroid I cannot help 



thinking that the great French naturalist was mistaken as to the 

 operculum.' 



The conviction steadily gains ground that Tryon cannot 

 possibly have seen some of the shells about which he writes. 

 The idea of suggesting that a shell with a stout bushy epidermis 

 could be a Purpura ! The idea of venturing to contradict the 



J.C., v., Tuly, 1888. 



