o80 UNIVALVE SHELLS 



2. M. * multiline ata. Shell gradually tapering; apex 

 generally much eroded ; whorls about seven, a little 

 convex, with numerous, filiform, elevated, subequal 

 lines, which are from ten to twenty in number on the 

 body whorl. 



Length nineteen- twentieths ; greatest width two- 

 fifths of an inch. 



Inhabits tributaries to the Delaware. 



1 found several specimens of this shell in Frank - 

 ford creek ; and professor Vanuxem presented me. 

 with others which he obtained from a creek in New 

 Jersey. The M. elevata (p. 176 of this work) from 

 its attributed specific characters, might be supposed 

 to be nearly related to this shell, but it differs in be- 

 ing of a more accurate conic form, the whorls being 

 flattened, and not convex as in this species, its raised 

 lines are also few in number. 



CYCLAS. Lam. 



1. C. *rhomboida. Shell transversely orbicular- 

 rhombiform, subequilateral, pale, with elevated some- 

 w hat regular transverse lines ; umbo not prominent. 



Breadth more than one-fourth of an inch. 



Inhabits lake Champlain. 



It is probable that this species attains to a somewhat 

 larger size than the two specimens from which the 

 above description was taken, and which were found 

 by Mv. Augustus Jessup. It is distinguishable from 

 C similisby its more rhomboidal form. 



2. C. *partumeia. Shell thin and fragile, trans- 



