CHAP. IV, ANALOGIES OF THE VOLUTIDiE. Ill 



ing treatises, are so well known to the majority of our 

 readers, that it would be superfluous again to repeat them. 

 But before we apply this theory to the group before us, 

 a previous question must be first disposed of, — namely, 

 upon what grounds we determine that the melon volutes 

 are the pre-eminent types of the whole family ? Now, 

 we do not regard this as a matter of speculative opinion ; 

 it must be determined, in fact, by the analogies which 

 the group possesses, as a whole, to other groups. The 

 following table appears to us to decide this questioij : — 



Analogies of the Zoophagous and Phytophagous 

 Gasteropoda. 



Families of the , „, ■^„i ru„ „ t^^^ Families of the 



Zoophaga. Analogical Characters. Phytophaga. 



MuRiciDiE. Typical. HELicioiE. 



TuRBiNELLiDiE. Sub-typical. Trochid^. 



fFoot of the animal excessively"! 

 I large ; tentacula very short ; eyes I 

 VoLUTiD.E. <j sessile; shell with an enormous V HALiOTiDiE. 



I body-whorl, and a short, nearly | 

 (^obsolete spire. J 



CvpR*:£DJB ("Shell smooth, glossy, partly cover- 7 ^.^.^r^^ 



L\PR£fD^. ^ ed by the animal's mantle. j ^^ATICIP.E. 



STR0.MBID.E. Animal with a respiratory siphon. TuRBioiE. 



Now, as the ear-shells are at the head of the Halio- 

 t'ldce, it consequently follows that the melons have the 

 same rank among the Volutidce. The perfect ana- 

 logy of the two families is equally remarkable, whether 

 we look to the animals or to their shells : nay, it might 

 be carried still further ; for as there are coronated and 

 smooth melon volutes, so are there among the ear- 

 shells, — one division of the latter having their per- 

 forations smooth, the other having them elevated or 

 coronated. 



(102.) We may now at once compare the five genera 

 of the VolutincB with the five primary divisions of the 

 whole family. 



