igip-] N. AnnandaIvE & B. Prashad : Gangetic Delia Molluscs. 245 

 Littorina melanostoma. Gray. 



1882. LitortJia melanostoma, VVeinkauff, " Die Gatt. Litoi'ina" in Che- 



mitz's Conch. Cab., p. 41. 

 1887. Littori)ia melanostoma, von Martens, Journ. Linn. Soc. ZooL. 



XXI, p. 170. 



This is by far the commonest of the Gangetic lyittorinidae. 

 It occurs in large numbers on grass and bushes exposed at low 

 tide, but submerged when the tide rises. The geographical range 

 extends to the Malay Archipelago. 



We figure the radular teeth (fig. 2a) ; their most remarkable 

 feature is the assymetrical form of the inner lateral tooth. 



Littorina subintermedia, Nevill. 

 (Plate XX, fig. 3). 



1884. Littorina conica var. sitbintermedia, Nevill, Hand-list Moll. hid. 

 Mus., II, p. 149. 



This form appears to be less like L. ccMiica and the true 

 L. inter tnedia than Nevill thought, and we think it best to regard 



a. 



h. 



Text-fig. 2. — Radular teeth of Gangetic species of Littorina. 



{a) L. melanostoma, Gray. (fe) L. subinter media, Nevill. 



(c) L. delicatula, Nevill. 



it as distinct. The shell is much thinner than that of either of 

 Philippi's species, and has a slightly transluscent appearance. It 

 is also narrower and more conical, and the sculpture is more deli- 

 cate. The columella is narrow, but has a very distinct spindle- 

 shaped depression upon its surface. The body-whorl is hardly 

 angulate. The colour of all the shells we have seen is pale-yellow- 



