1921.] N. AnnandalE & B. Pkashad : Indian Molluscs. 12 5 



I. Sliell bearing a spiral row of large spines on some of 



the whorls in addition to the microscopic sculpture. 



.\. Spines restricted to basal whorls of the spire only ; 



the whorls evenly inflated and not keeled 5. eclnnuta. 



B. Spines present on almost all the whorls including 

 the body-whorl ; the whorls especially those of 

 the spire ridged or keeled in the middle 5'. uriinfii. 



II. Shell without anv definite spines, with or without a 



definite spiral sculpture. 

 .\. .Shell elongate-ovate, nearly cylindrical. 



/. Shell rather small and narrow (25X tj mm. I ; sub- 

 perforate, rimate ; with the whorls of the spire 

 increasing regularly and having a microscopic [ana. 



sculpture ... ... ... 5'. h linger fo I'd i- 



II. Shell much larger (4.3 X, 5 mm.), imperforate; with 

 the whorls of the spire increasing irregularly 

 and with relatively large pits on the surface of 

 the shell ... ... ... ... 5'. monilifera. 



B. Shell ovate or ovoid never elongate cylindrical. 

 /. Mouth opening large, more thah \ the size of the 

 body whorl. 



A. Body-whorl not at all flattened on the ventral 



surface, and with a very small boss separat- 

 ing the mouth from the body-whorl ... S. soliita. 



B. Body-whorl distinctly flattened on the ventral 



surface, at least in its .interior half, and with a 



well-developed boss separating the mouth froin 



the bod\- whorl. 



1. Shell small (l-(. mm. long), with a very short 



spire and with a well-developed boss above 



an elongate circular mouth ... ... .9. iituiiim. 



1. Shell large, over t, mm. long, subventricose- 

 ovate. with a short spire, the whorls of the 

 spire increasing irregularly ; a greatly swol- 

 len body-whorl and a biangulate suboval 

 mouth ... ... . ... S. klaiijordiaiia. 



V Shell large, .^ mm. long, elongate-ovate; the 

 spire more produced, with regularly increas- 

 ing whorls ; body-whorl less tumid and the 

 mouth nearly circular or having onl)- a 

 faint notch above .. ... i". minima. 



II. Mouth-opening small, less than ), the size of the 



body-whorl. {ana. 



A. Shell without any spiral pitted sculpture ... S. 7food>iiasoni- 



B. Shell with a definite spiral pitted sculpture. 



1. Shell minute, 22 mm. long, with a very short 



spire and a bluntly rounded apex ... .S'. nana. 



2. Shell relatively large, with a prominent conical 



spire and an acuminate ape.x. 



a. Shell globose-conical, having ;i large and 



swollen body-whorl, and with a well-de- 



\eloped boss ... ... S. deltae. 



b. Shell ovate, acute, having a smaller and not 



creatly swollen body-whorl, and with a 



much smaller boss ... S. foveolatu. 



Stenothyra echinata, Aniiandale and Piashad. 



1919. Stenothyra echiiiatu. .\nnandale and Prashad. Rec. hid. Miis. 

 X\'l, p. 247, pi. \x, fig. 5. 



S. echinata, as was noted in the original description of the 

 species, is closely allied to S. deltae (Benson), which also shows 

 traces of spines in some specimens, bnt is easily distinguished by 



