IX. THE INDIAN SPECIE. S OF THE 

 GENUS TRICULA, BENSON. 



By B. Prashap, D.Sc, Offg. Superintendent, Zoological 

 Survey of India. 



In a recent paper' I discussed at length the systematic position 

 of the genus Tricula, Benson, and further notes on the same subject 

 were added by Dr. Annandale and myseU"* in our revision of the 

 Indian genera of the family Hydrobiidae In this paper I propose 

 giving a revised description of the shell of T. inontana, Benson- -the 

 tj'pe-species of the genus, together with an account of a new species 

 which was chscovered by Dr. F. H. Gravely in the Nerbudda River 

 in the Central Provinces. A reference to this second species was 

 made by Dr. Annandale in his recent paper.' 



The two species may be distinguished by the help of the follow- 

 ing key :~ 



I. .Shell conico-ovale, iwiix' ;is lung ,is bruad ,■ wilh scry fine 

 ribs; whorls not greatly swollen, body-uhorl in dorsal 

 view subtrija^onal, only a little longer than broad ; mouth 

 nearly J the height of the body-whorl, acutely pointed 

 above and with the columellar callus of unequal width ... T. mnntana. 



i. Shell elongate-ovate, not more than 15 as long as broad ; 

 smooth; whorls \erv tumid; body-whorl in dorsal view 

 band-shaped, about twice as long as broad : mouth only 

 a little more than i the height of the body-whorl, narrowly 

 rounded above and with a columellar callus of .ibout the 

 same width in its entire length ... T. gravclyi. 



I am unable to add any notes on the var. curta of Nevill,* 

 a variety of T . moniana based by Nevill on two specimens from 

 the Jhiri valley at an altitude of 3,000 feet in North Cachar, 

 collected by Colonel H. H. Godwin- Austen, as I have not succeeded 

 in tracing the specimens in the Indian Museum collection. 



Tricula montana, Benson. 



1843. I'riciila montana. Benson, Calcutta Joiirn. Sat. Hist., 111. p. 4O7. 

 1862. Tricula montana, id.. .Ann. Mag. Nat. Hist. (3)X, pp.415, 416. 

 1876. Tricula montana. Hanley and Theobald. Condi, hid., pp. xvii and 



62, pi. civ, (ig. 5. 

 1S85. Tricula montana, Nevill, op. cit., p. O4. 

 1015. Tricula motitana. Preston, Faun. Brit. Ind. Freslm\ Moll., p. 68. 



Nothing is known about this interesting mollusc beyond the 

 original descriptions of Benson and the poor figure of the ventral 



' Prashad, Rec. h.d. Mas.. XVIIl, pp. 221, 222 (1921). 

 2 .\nnandalc and Pr.ishad, Rec. Ind. Mas., XXll, p. 3 (1921;. 

 8 .\nnandale. Ind. Journ. Med. Researcli, V'lll, p. i(i^ 0920). 

 * Nevill. Hand List Moll. Ind. M-is.. II, p. 64 (18851. 



