PLEUROCEKA. 135 



Observations. — Two specimens of this small species came with 



bivittatum, herein described, mixed with the young of other species. 



It is rather lararer than it and, although very close, may be _. „.„ 

 ° ^ •' •' Yig. 2o0. 



distinguished t)y difference of size, being more pyramidal, 

 having a darker epidermis, and in the aperture being more 

 rhombic. Two bands only are visible on the exterior, but 

 the interior of the larger displays a third close to the base 

 of the columella, making a spiral turn round it. The aper- 

 ture is about three-eighths of the length of the shell. It is very 

 different from Melania jmmila (nobis) described in Trans. Am. Phil. 

 Soc. y. X, p. 86, which indeed belongs to the genus Lithasia. — Lea. 



81. P. opaca, Anthony. 



Melania opaca, AXTHOXY, Proc. Acad. Nat. Sci., p. 58, Feb. 1860. BiNNET, Check 



List, No. 189. Bkot, List p. 38. Reeve, Moiiog. Melania, sp. 381. 

 Melania iostoma. Axthoxy, Proc. Acad. Nat. Sci., p. 02, February, ISjO. Binney, 



Check List, No. 152. Brot, List, p. 31. Keeve, Monog. Melania, sp. 351. 

 Melania nigrostoma, Anthony, Reeve, Monog. Melania, sp. 403, 3G7. Brot, List, 



p. .38. 

 Trijpanostoma Tennesseense. Lea, Proc. Acad. Nat. Sci., p. 175, 18G2. Jour. Acad. 



Xat. Sci., v, pt. 3, p. 281, t.37, f. 100. Obs. ix, p. 103. 



Melania iostoma. — Shell ovate conic, smooth; spire obtusely 

 elevated; whorls about six, subconvex; body-whorl exhibiting un- 

 commonly strong lines of growth, curved and varicose; color, 

 greenish-olive, shining; sutures distinct; body-whorl strongly but 

 not sharply angulated on the middle, aperture broad ovate, within 

 ^. liglit pui'ple, which becomes very deep on the columella, 

 which is regularly rounded ; outer lip somewhat produced, 

 and having a well developed sinus at base. 

 Habitat. — Tennessee. 



Observations. — This species approaches nearest in form 

 and color 31. glans (nobis), now changed to glandnia, from 

 which it differs in being less globular, of a lighter color generally, 

 and by the angulated body- whorl. Compared with 3r. jnufjrds, Lea, 

 it is less obese, more elongate and has not tlie rapidly attenuating 

 spire of that species. From all others it is readily distinguished. — 

 Anthony. 



The following species, which is figured from a type specimen 

 also, will, I am confident, prove to be the young of iostoma. 



