24 PROCEEDINGS OF THE ACADEMY OP [1879. 



acute, oblong-conic, sides plamilate; suture distinctly and nar- 

 rowly marginate; whorls six, snb-planulate, slowly and regularly 

 increasing, the last rather large, not descending in front ; aperture 

 oblique, ovate-Innate, more than a third the length of the shell; 

 parietal wall with a prominent, strongly-compressed lamina ; pe- 

 ristome thin, simple, regularly curved ; columella slightly twisted, 

 depressed, armed with a sub-median, nearly horizontal, acute tooth- 

 like fold ; palate with numerous irregularly disposed denticles. 



Length 2j, major diameter H mill. 



The single example before me differs so much from any other 

 species, that, after some hesitation, I have concluded to describe 

 it as new. 



It is shaped almost precisely like ajffinis, but has the palatal 

 denticles, and acute, columeliar, tooth-like plait of nitida. 



Tornatellina perplexa, sp nov. 



Torndtellina bilamellata, Schmeltz (not Anton), Cat Mus. Godeff. No. 

 5, p. 90. 



Shell small, oblong-conic, imperforate, fragile, glossy, pellucid, 

 smooth, pale brownish-horn color; spire oblong-conic, with suh- 

 planulate outlines; apex obtusely rounded; suture distinctly 

 linear; whorls six, convex, moderately and regularly increasing, 

 the last eonvexly rounded, not deflected in front; aperture ob- 

 lique, ovate-lunate, about one-third the length of the shell ; peris- 

 tome thin, straight, regularly curved ; columella depressed, tor- 

 tuous, bi-dentate, the basal tooth small, the upper, which is sub- 

 medial, is large and prominent ; parietal region with a large, 

 prominent, curved lamina ; palate garnished with more or less 

 numerous irregularly disposed denticles. 



Length 2, major diameter 1 mill. 



Mr. De Gage sent a number of these shells of all ages, and I have 

 myself collected Uie same species at the Cook's and Society 

 Islands. 



Its close resemblance to nitida has perplexed me so much that 

 I have long hesitated about the propriety of separating the two 

 as distinct. 



It may, however, be distinguished from that species by its more 

 dilated and Indent ate columella. The upper tooth is also larger, 

 and less acute than in nitida. Some examples have the palatal 

 denticles mounted on delicate, longitudinal lines of callus. Others 



