OP CONCHOLOOY. 109 



Prof. Haldeman remarks : " There appears to be no reason 

 to doubt the locality of this specimen ; at any rate, Say was 

 satisfied upon this point, and I accordingly admit it as indige- 

 nous upon his authority. I have compared the original speci- 

 men with shells from Calcutta, and find that it differs as little 

 from them as they do from each other. If this is not the Ben- 

 galensis of Lamarck, it must have the name given to it by Say, 

 that of Swainson having been previously given to a fossil 

 species." 



I have made many comparisons of this species with the Ben- 

 galensis of Lamarck without detecting the resemblances which 

 misled Messrs. Say and Haldeman. The history of almost any 

 genus in Conchology shows a great progressive development 

 of acute discrimination in the study of its species, and perhaps 

 no group of shells can be cited as a more instructive example 

 of this substantial progress than the one of which this is a 

 member. In the time of Linnaeus, his Helix vivipara was fully 

 understood to embrace all the banded Viviparse, but from it 

 was soon separated the fasciata, Mull, (achatina, Drap.) These 

 two species became afterwards the types of two subdivisions, 

 constituting the great fasciate group of the restricted genus 

 Vivipara (from the old genus has been separated Melantho, 

 Tulotoma, Lioplax, etc.) These divisions are distinguished in 

 all their species by a marked difference in the convexity of the 

 whorls, and in their rapidity of increase in size. 



The first type, V. vivipara, is represented in America by at 

 least three species, V. lineata, Val., V. interiexta, Say, and V. 

 Bermondiana, D'Orb. These are all globose species, with 

 rapidly enlarging whorls, very convex, with deep sutures. V. 

 lineata has been almost constantly, to the present time, con- 

 founded with V. vivipara by American authors; but its very 

 constant specific difference was long since pointed out by 

 Kiister in his "Conchylien Cabinette." The shell herein de- 

 scribed is confounded by Say and Haldeman (partly) with 

 this division, whereas it undoubtedly belongs to the other. 



The second division of the group, represented typically by 

 V. fasciata, has been enlarged by European naturalists by the 

 elimination of several distinct species, among which may be 

 cited V. pyramidalis, Jan. The shells of this division have 

 higher spires, the whorls much less convex and increasing in 

 size more gradually. This group is represented in America, 

 so far as we are aware, by one species only, the one now de- 

 scribed. 



Both divisions are represented by exotic species, and it 

 remains to distinguish V. Waltonii from V. Bengalensis, which 

 belongs to the same division. The most striking difference is 

 that of color, Waltonii having the warm reddish tints of the 



