CHAP. III. THE PURPURIN^. 71 



Other. VexUla represents^ in outward form, and most 

 perfectly in colour_, Harpula vexillum, just as Harpa 

 typifies the crowned volutes. Oniscia and Cyprcecmsis 

 are perfect counterparts of each other; while Cassidaria 

 and Cassis complete this system of analogies. If any 

 doubt existed as to the absolute union of Oniscia and 

 Cassidaria in regard to affinity, it is set aside by a re- 

 markable shell obligingly sent me by ^Irs. Stuchbury, 

 where the characters of both are united. This is of 

 much additional importance, because it shows that Cas- 

 sidaria does not form one of the five types of the Cas- 

 sirne, but merely leads to them from the Nas since. 

 These, therefore, are the grounds upon which we have 

 adopted ]\Ir. Stuchbury's genus Cyprcecassis. And while 

 we return his opponents our best thanks for stimulating 

 our attention to the subject, and thus detecting a mate- 

 rial error of our ow^n, w'e sincerely trust that he himself 

 will prosecute his researches with the same ability and 

 w^th the same success ; to the true advancement of our 

 favourite science of Malacology.* 



(62.) The PuRPURix^E form the next sub-family 

 in our arrangement. They include shells whose general 

 form closely resembles the BucciniiKe, or whelks, but 

 with this difference, — that the pillar, without being ele- 

 vated round the margin, is very much thickened, yet 

 always more or less flattened and depressed — not, as in 

 the generality of shells, convex. This, in truth, is the 

 only character seen in the shells, by which this assem- 

 blage is in any way linked together. For the rest, the 

 spire is almost always very short; the aperture large and 

 wide; the inner lip not otherwise developed than by a 

 transparent polish spread over it, wdiich is sometimes 



* I cannot pass over this opportunity of publicly expressing my obliga- 

 tions to his worthy brother, Mr. S. Stuchbury, of Theobald's Road, one of 

 the tirst commercial naturalists in I.,ondon, for the free use he has always 

 given me of any interesting shells in his collection, without the necessity 

 of purchasing them ; a liberality not always met with. With him, I have 

 named a series of types of the greater part of the new genera here defined, 

 and 1 feel assured he will supply them to collectors on the most fair and 

 moderate terms. 



F 4 



