CONTEIBUTIONS TO CONCHOLOGY. 



No. 8. 



Descriptions of new species of Partula and Aciiatinella, 

 By C. B. Adams, Professor of Zoology, &c., in Amherst 

 College. Read before the New- York Lyceum of Natural 

 History, Oct. 21st, 1850. 



Partula diminuta. Shell rather thick, ovate-conic ; trans- 

 lucent, horn-colored, sometimes reddish, with a thin shining 

 brownish horn-colored epidermis, which is much interrupted 

 by transverse stripes ; with the tip white ; with unequal, ir- 

 regular, rather coarse transverse striae, and numerous exces- 

 sively minute impressed spiral lines ; apex subacute ; spire 

 rather short, with the outlines slightly curvilinear ; whorls 

 five, a little convex, with a moderately impressed suture ; last 

 whorl moderately oblique : aperture rather small, subovate, 

 with a tubercle on the middle of the intruding part of the last 

 whorl: lip much thickened, but narrow, with a regularly 

 rounded surface : umbilicus small. 



Mean divergence 58° ; length .63 inch ; greatest breadth 

 .36 inch ; least breadth .3 inch ; length of the aperture .23 

 inch : the corresponding dimensions of another specimen are 

 60° ; .525 inch ; .28 inch ; .32 inch ; .21 inch. 



Hab. — ? 



This species resembles a variety, (P. anriculala Brod.,) oi 

 P. Otaheitana Brug-., but is more slender, as well as smaller. 



AcHATiNELLA MAGNA. Shell thiclv, ovatc-conic, elongate : 

 blackish brown at the apex, reddish brown on the middle 

 whorls, and ash-colored on the lower whorls : with unequal, 

 irregular, very coarse transverse striae, with close-set trans- 

 verse arcuate ribs near the apex, and some indistinct raised 

 spiral lines on the lower part of the last whorl : apex subacute : 

 spire rather long, with the outlines quite curvilinear : whorls 

 seven, rather convex, with a well-impressed suture ; last whorl 



