COiNTHIBUTIONS TO CO^^CHOLOGY. 



No. 7. 



Descriptions of supposed new species of Land Shells, which 

 INHABIT Jamaica — continued jrom page 98. By C. B. Adams. 

 April, 1850. 



Hrlicina ampliata. Shell conic : whitish (?) : with a few ex- 

 cessively fine striae of growth ; otherwise smooth and shining : apex 

 subacute : spire much elevated, with the outlines moderately curvi- 

 linear : whorls five and one half, a little convex, with a distinct su- 

 ture ; last whorl subangular, anteriorly subplanulate : aperture trans- 

 versely much dilated, depressed in the upper part of the right side : 

 labium with a large thick deposit. This shell resembles //. Jamai- 

 censis Sotvb., but is much larger, much less globose, and more conic. 



Mean divergence about 90° ; height .6 inch ; greatest breadth .67 

 inch ; least breadth .57 inch. 



Helicina pusilla. Shell depressed globular : horn color for 

 brownish (?) : with excessively fine striae of growth : apex subacute : 

 spire moderately elevated, with the outlines curvilinear : whorls more 

 than four, a little convex, with a distinct suture : aperture rather 

 large, well rounded in the right side, somewhat sinuate in the left 

 side; labrum thin, moderately dilated, well reflected, with a deep 

 curved incision, similar to that oi H. palliata, and next below the co- 

 lumella, the end of which is sickle-shaped. This species is much 

 less discoidal than H. macilenta. 



Mean divergence about 120^^ ; height .16 inch ; greatest breadth 

 .25 inch ; least breadth .2 inch. 



Cylindrella humilis. Shell cylindrical in the lower two-fifths, 

 tapering above : pale horn color ; with rather numerous oblique, 

 nearly straight equidistant fine elevated transverse lines : spire trun- 

 cate, with the loss of whorls : whorls remaining eight to eight 



and one-half, very convex, with a well impressed suture ; last whorl 



subangular anteriorly, scarcely produced from the penult whorl ; 



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