170 TESTACEOUS MOLLUSCA. 



the specimen before me three or four granular lines radiate down 

 the posterior sloped 



N. Recurva. Com: Jour. A. N. S. Phil. 6. t. 11. /. 21. 

 Oblong, concentrically striated towards the beaks, and obliquely 

 so towards the ventral edge : anteriorly rostrated and recurved, 

 posteriorly rounded, beaks subcentral. 4. — West Indies. 



N. Sapotilla. Gould. Mas. p. 100. fo 61. Elongated 

 ovate, translucent, subequilateral, posteriorly rounded, anteriorly 

 narrowed and compressed ; the anterior dorsal edge straight and 

 rendered sharp by the compression of a very uaiTow portion of the 

 margin ; subrostrated, tumid at the beaks with only a slight 

 flexure under the anterior tips ; smooth, polished, pale yellowish 

 green : teeth about sixteen on each side. | . . -^^. — North 

 America.' 



N. Navicularis. Couthouy. Host. Journ. N. H. 2. t. 4. 

 f. 4. — Gould. Mas. p. 103. Small, smooth, fragile, subequilateral, 

 greenish yellow, posteriorly rounded, anteriorly feebly beaked ; 

 slightly truncated, ventral margin very convex ; beaks prominent ; 

 inside white and glossy, the hinge with from sixteen to eighteen 

 teeth. ^. — North America. 



N. Nasuta. So7v. in Conch. Jl. f. 12.— Reeve, t. 85. /. 12. 

 Oblong, white, very finely striated transversely ; posterior side 

 rather shorter than the anterior, rounded : anterior acuminated, 

 slightly turned upwards, with an elongated transversely striated 

 dorsal area. | . . f^: — li^ast Indies. 



N. Fabula. Sow. Conch. II. f. 13.—Beeve. t. 85. /. 13. 

 Ovate, white, obhquely striated, nearly equilateral, posterior side 

 rounded, anterior acuminated, slightly turned upwards, with two 

 ridges passing from the umbones to the acuminated extremity, the 

 upper of which is crenated, forming an anterior dorsal area. 



i 2 



4 • • 5* 



N. Striata. Sow. Conch. II. f. 16. — Recce, t. 85. f. 16. 

 Ovate, white concentrically striated, nearly equilateral, the dorsal 

 slopes nearly equal ; posterior side slightly acuminated, rounded ; 

 anterior side acuminated, with an indistinct dorsal area. \ . . \'^. — 

 China. 



N. Mauritiana. Sow. Conch. 111. f. 17. — Reeve, t. 85./. 17. 

 Ovate, white, concentrically grooved, nearly equilateral, posteriorly 

 rounded, anteriorly acuminated : dorsal slope nearly equal on both 

 sides, ^ . . |. — Mauritius. 



N, LiMATULA. Say. Am, Conch, t. 12. — Gould. 3Ias. p. 98. 



1 Add likewise the N. Glacialis. Gray, in W. S. t. 2. fo 6. 



2 See too the Myalis of Couthouy in Boston. J. of N. II. 2. 

 t. 3. /. 7.— Gould, p. 99. 



