PLATE CXLIX. 



or without any trace of the marginate edge so conspicuous in the 

 shell at this time before us. We are not, however, to forget, that 

 the progressive growth of many well known species of the shell tribe 

 is to be distinguished by the changes that take place in the form of 

 the lip, such as its greater expansion or dilation, and not unfrequently 

 in the formation and elongation of distinct processes, of which 

 examples occur in the genus Strombus ; examples in which the 

 younger shells have an acute simple edge, while in the adult shell 

 the lip is furnished with a range of elongated processes of very 

 striking figure as well as magnitude. The lip also of shells of other 

 tribes are known to increase in thickness as the animal inhabitant 

 becomes older, and where there is no other indication of its increasing 

 growth, except that which becomes apparent from the increasing 

 bulk of the shell itself. 



Upon the whole, therefore, for those reasons we are rather 

 inclined to admit this new conchological acquisition, for such it 

 really appears to be, as a variety of the Linnaean Bulla Achatina, 

 than as a species distinct from that shell. The deviation it presents 

 in its reflected lip is certainly worthy of consideration : we must 

 regard it as a novelty, and were it not for this peculiarity we should 

 from the general aspect of the shell be more inclined to place it in 

 the genus Achatina of Lamarck than with the Bulla? of Linnaeus ; 

 at the same time it must be allowed, that this anomaly could not be 

 justified, or that at least the definition of the genus, must in that 

 case be first qualified by the omission of the words " labro acuto? 

 nunquam reflexo and we therefore place it in the Bulla genus, as 

 a variety of the Linnaean Bulla Achatina. 



