210 



SHELLS AND SHELL-PISH. 



PART I. 



These and their analogies may be arranged in the fol- 

 lowing table : 



Genera 



of the 



TURBINJE. 



TURRITELLA. 

 SCALARIA. 



SdSSUR^A. 



MELAMPOS. 



Analogies of the TURBINE. 



Sub-families 



Analogies. of the 



TURBID.E. 



"SESs&si " >n8cr ] *"- 



Spire excessively long. MELANIAN^E. 



Mouth circular, margined. TURBINE. 



Genera 



of the 



MELANIAN.K. 



Melania. 

 Cerithidea. 



Palndomus. 



We introduce two series of analogies in this table, 

 because one will better illustrate what may be thought 

 obscure in the other. The two first set of analogies, 

 Turbo and Turritella, are particularly strong; for we thus 

 find the needle-like Melaniance represented by Turritella,' 

 and Turbo by Ampullaria, both equally ventricose and 

 turbinate. The thick or margined aperture, again, of 

 Scalaria and Cerithidea exist in no other groups. It 

 must be remembered, also, that the Turbida, as a family, 

 is the cyclostiform or circular-mouthed group of the 

 phytophagous tribe ; and this character runs through the 

 whole group, with the exception of Melampus : Sets. 

 surella and lanthina have the strongest analogy ; and 

 these, with Planaxis, have the most effuse apertures of 

 all their congeners. We must confess, indeed, that, but 

 for the discovery of Scissurella, we had long imagined 

 that Planaxis formed the most aberrant genus of the 

 TurbincB. The last set of analogies is those between 

 Melampus, Thallicera, and Paludomus :. it is not very 

 strong ; yet, as they are the only shells with plaits on 

 the pillar, they represent the volutes and the land Auri- 

 cula; while it seems that Mr. Say has discovered an 

 Anculosa, whose pillar bears a plate or fold precisely 

 analogous to that in Thallicera. 



(195.) Of the next sub-family, represented by the 

 beautiful and delicate lanthince, or oceanic snails, little 



