170 SPECIFIC 



Habitat unknown. 



The general appearance of the shell bespeaks it 

 a Helix, and not a Trochus as it has hitherto been 

 designated. The convexity of the columella, and 

 the upright situation and form of the ajjertui'e, 

 irresistibly confirm the first impression. 



PLATE XXIV. 



This plate is intended to point out to beginners 

 in Conchology the great difference which exists, in 

 certain species, between the shell in its young, 

 unfinished state, and the same arrived at its per- 

 fection. The examples adduced are among the 

 most conspicuous, but there are many others of 

 which it would be very beneficial to students to 

 acquire an early knowledge. 



The mature specimen of Buccinum ViOcx is 

 given in Plate XXI. Fig. 3. 



