CHAP. III. 



THE BUCCININ^ffi;. 



73 



lip the last indication of Ricinula. The connection^ 

 again, of these singular shells to Concholepas seems to be 

 effected by our Ricinula planospira\, which has the 

 spire nearly obsolete. This, as we believe, is the true 

 course of the circle, the contents of which find their re- 

 presentatives in the sub-families. It really seems ad- 

 visable that the sub-genera of Ricinula, Nassa, Triton, 

 and such varied groups, should be characterised when 

 the science is somewhat more advanced. 



(64.) There is one set of analogies, however, result- 

 ing from this disposition of the PurpuriniB, which we 

 cannot omit, because it illustrates that sub-family by 

 which they are represented in the circle of the Turhi- 

 nellidcE, — namely, the PyruUncE. This will also save 

 much useless repetition when we come to speak of the 

 latter group. 



Analogies of the PuRPURiNiE and the Pyrulin^. 



Genera of the 



PURPt'RlN.E. 



Pillar flattened. 



Concholepas. 



Monoceros. 



Microtoma. 



Purpura. 

 Ricinula. 



Analogical Characters. 



r Shell smooth; spire excessively T 

 -5 small, scarcely projecting; aper- V 

 c ture very efifuse. j 



Spire more lengthened, conic, 

 r Shell smooth ; spire small ; aper 

 ■5 ture very effuse ; the basal ca 

 C nal narrow and almost obsolete. 



Shell ponderous, rough, often 

 spired ; basal canal wide, and 

 fully developed. 



Pillar, or inner lip, toothed. 



{ 



^ 



Genera of the 



Pyrlltn^.. 

 Pillar convex. 



Ficula. 



Pyrula. 



Rapella. 



Myristica. 

 Cuma. 



Considering that these sub-families belong to two supe- 

 rior divisions, of which each is the most aberrant type, 

 the coincidence of each agreeing in their details, is not 

 a little remarkable. 



{Q5.') The BucciNiN^, or whelks, form the fifth and 

 last division of this family : they are known from the 

 murexes by having no varices, and from the PurpurincB 

 by the pillar not being flattened : they are generally re- 

 cognised by the abrupt termination of the base, v^'hich 

 is deeply notched. They are nearly all smooth shells, 



