124 Records uf the Indian Museum. [Vol. XXII, 



The soft parts. — The foot i:^ long and narrow, fusiform as a 

 whole but with the antero-lateral an^iles produced. The posterior 

 extremity is pointed or produced into a filament. The central 

 region of the sole is somewhat dilated, the dilation corresponding 

 with the position of the operculum on the upper surface. The 

 snout is long and cylindrical, extremel}' mobile and extensile. 

 The tentacles are filamentous and have the eyes situated on slight 

 prominences at their base. The male organ, which is situated on 

 the " neck, " lacks a lateral appendage. 



Subgenus Stenothyra, s.s. 



18,56. Xematiira, Benson, Joiirn..As. Soc. Bengal \ . p. 781. 



1856. Stenotliyra. Bcjison, Ann. Mag. Nat. Hist, str 2, Wll, p. 



496. 



1557. Nematiiva, Gray, Giiiile Syst. Dist. Molt. Brit. Mus. 1. p. yo. 



1558. Xematnra, Adams, H. and A.. Genera Rec. Moll. I. p. .542. 

 1S58. Stenothyra, ib., id., II, p. 626. 



i8(i2. Nematura, von Fraueni'cld, Vei-li. Zool.-bot. ges. Wien XII. 



pp. 1157, 1:58. 

 1S65. Stenothyra, Stimpson. Stnittisonian Misc. Pub. No. 201, p. 40, 

 1885. Stenotliyra, Ncvill, Hand-List Mott. Ind. Miis. 11, p. 42. 



1857. Stenotliyra, Fischer, Man. Conchyliot., p. 731. 



1Q15. Stenotlivra, Preston, Faun. Brit. Ind. Freshw. Moll., p. 79. 



The body-whorl of the shell is distincth^ flattened on the ven- 

 tral surface and the aperture is relatively small and not at all prom- 

 inent, the peristome being not at all or onl}' slightly thickened or 

 dilated and of regular subcircular or oval outline. The upper and 

 outer region of the mouth is separated from the outer edge of the 

 whorl by a well-defined boss or triangular area that is usually 

 more or less tumid. The periostracum is relatively thin and, ex- 

 cept for the frequent occurrence of punctured lines and of the horny 

 spines in .some species, smooth. The operculum is oval or subcir- 

 cular. The radula has the generic characters well developed. 

 The foot is produced into a filament behind. 



Type-species. — Stenothyra dcltae (Benson). 



The species of this subgenus have hitherto stood in need of 

 revision, and in recent years several quite unnecessary names have 

 been set up by Preston. The number actually known from the 

 coasts of India have, therefore, proved, as Annandale and Kemp 

 suggested,' smaller than had been supposed, but we have to des- 

 cribe several hitherto undescribed forms. 



We can now recognise I2 Indian species but are doubtful 

 about the Burmese species described as Nematura puncticulata by 

 Gould. ^ Of these species we have examined the types in most 

 cases and authentic specimens in others. The Indian species, with 

 the exception of Gould's Nematura puncticulata, which we are 

 unable to recognise, may be distinguished by the help of the fol- 

 lowing key : — 



I .\nnandale and Kemp. .Mem. Ind. Mus. V. p. 345 (19161. 

 ■^ Gould, Proc. Boston .Vat. Hist. Soc. II. p. 220 (1847). 



