14 



VIVIPARA. 



4. Western ; confined to the Middle or Western States. 



V. subcarinata, V. decapitata, 



V. regularis, V. subglobosa. 



5. Western and Southern ; not found in Canada or New Eug 

 land, nor perhaps to the east of the Alleghanies. 



V. ponderosa, V. subpurpurea, 



v. coarctata, V. vivipara. 



The species are grouped in the folloMng manner : — 



Shell nodulous § 1. V. magnifica. 



Shell carinated § 2 



Shell simple. 



a. elongate ovate. 



§3. 



b. globose § 4. 



V. multicariuata, '' 



V. cyclostomatiformis, 



V. subcarinata. 



V. ponderosa, 

 V. decisa, 

 v. coarctata, 

 V. subpurpurea, 

 V. incrassata, 

 V. vivipara, 

 V. intertexta, 

 V. troostiana, 



wareana, 



coosaensis, 



decapitata, 



regularis, 



V 

 V 

 V 

 V 



V. subglobosa. 



Fig. 19. 



§ 1. Shell nodulous. 



ViTipara magnifica, Conkad — Shell subovate, ventricose, with 

 two spiral bands of prominent tubercles on the body whirl, and one re- 

 volving near the base of each whirl of the spire ; 

 suture profoundly impressed, margined by an obtuse, 

 subnodulous, prominent line ; lines of growth very 

 oblique and prominent ; obscure spiral striae ; epider- 

 mis olive ; within bluish, often with purple bands. 



A beautiful species when perfect, occurring in vast 

 abundance on the masses of calcareous rock, which 

 have fallen from the strata above into the Alabama 

 River at Claiborne. I found it living only in such 

 situations, and exclusively within a range of six or 

 eight miles. In the Tombeckbee or Black Warrior 

 Rivers, I never observed a specimen of it, although I 

 searched particularly for it on the rocks at St. Ste- 



Puludina magnifica. 



phen's. Conrad. 



