254 Records of the Indian Museum. [Vol. XVI, 



rather longer and more slender, (c) The siphon is shorter than 

 the shell. 



The whole animal is transluscent white, there is a tinge of 

 pale grey on the siphon and the dorsal surface of the foot. The 

 eyes are small but quite distinct. 



The radula (fig. 6c) is very similar to that of N . denegabilis 

 (fig. 6b) and A^. oyissaensis (fig. 5a) ; all of which we figure. The 

 lateral teeth have two distinct branches, which are quite smooth. 



N. orissaensis var. depauperata lives in creeks of brackish 

 water (sp. gravity corrected to I5°C. i oii75-i*oi725) on a 

 muddy bottom at a depth of 4-6 fathoms. It crawls with ex- 

 treme rapidity both in water and on damp surfaces, and can 

 float adhering shell downwards to the surface film by means of 

 the foot. 



Type-specimen : M ^-4-- in the collection of the Zoological 

 Survey of India. 



Locality. — Kaikal Maree near Port Canning, Gangetic Delta; 

 17th July, 1918. 



Family RINGICULIDAE. 



Genus Ringicula, Deshayes. 



1S44. Ringicula, Hinds, Proc. Zool. Soc. Lojidon, XII, p. 97. 



1875. Ringicula apicafa, Nex'ill, Joiivn. As. Soc. Bengal, WAV, (ii), 



p. loi. 

 1S7S. Ringicula, Morelet, 'Journ. de Conch., { },) X\'I1I (.\x\i), pp. 



1 13-133, pis. v-viii. 

 1878. Ringicula ( Anatomic de l/animal), Fischer, Ibid., pp. 114-115. 

 18S4. Ringicula, Watson, Journ. Linn. Soc. London, XVII, p. 291. 



Ringicula caeca, sp. nov. 



(Plate XX, fig. ID). 



The shell is small, very solid and of the usual shining white 

 colour. The spire is narrow, conical and sharply pointed, about 

 half as long as the body- whorl, which is relatively broad and 

 nearly square. Tlie main axis of the shell occupies a line much 

 nearer the inner than the outer margin of this whorl, which pro- 

 jects inwards at an angle from the base of the spire. The suture is 

 impressed and the whorls somewhat flattened outside it. The 

 mouthof the shell is contracted but relatively long, extending back- 

 wards at an acute angle with the main axis to a point at about 

 four-fifths the length of the body-whorl. The lips are very thick. 

 The outer Hp runs nearly straight for the greater part of its length, 

 and turns inwards somewhat abruptly, but at an angle less than 

 a right angle, in front; at the point at which it does so it bears a 

 broad oval prominence. The outer callus extends about half 

 way up the outer surface of the shell, and is strongly corrugated. 

 The siphonal notch is well developed, but not very prominent. 

 The columella is oblique and has three very prominent folds ; 

 the posterior fold is very broad, the median fold ridge-like and 



