376 MESSES. MELVILL AND STANDEN ON [June 18, 



Potamides (Pirenella) conicus Blainv. 



Var. cinerascens Pallas. 

 P.G., occasional. Originally described from the Island of Karak 

 in the Gulf. 



Potamides (Pirenella) layardi A. Ad. 



Yar. bombayanus Sowb. (sp.). 

 I. Bombay. Both the type and the variety recorded. 



Potamides (Cerithidea) rhizoperarum A. Ad. 

 I. Bombay. On mangrove-roots. 



Triforis acutus Kien. 



M.C. Charbar. 

 I. Karachi. 

 Most abundant and variable in coloration. 



Triforis cingulatus A. Ad. 



P.G. Bushire. Gulf of Oman, Maskat, 10 fathoms. On 

 muddy rocks from low- water to 50 fathoms. Also (in the Gulf) 

 amongst shell-growth on the telegraph-cable. 



Triforis corrugatus Hinds. 

 P.G. Gulf of Oman, Maskat. 

 I. Karachi. 



Triforis idoneus l , sp. n. (Plate XXII. fig. 17.) 

 T. testa angustefusiformi,solida,calcareo-alba; (infract ibus forsan 

 quatuordecim, quorum apicales . . . ?, cceteris (undecim) omnino 

 regulariter spiraliter triseriatis, cancellatis, suturaliter impressis, 

 ad juncturas nodulifero-gemmatis, nodulis regularibus, rectis, 

 ultimo anfractu serie quarta prwdito ; apertura ovata ; columella 

 crassa ; canali brevi, paidliilum recurvo. 

 Long. 10, lat. 2*50 mm. 

 Hob. Linjah Anchorage, .5 fathoms. 



This Triforis, distinguished by its uniform chalky whiteness and 

 regular rows of gemmuled cancellations, coarse, uniform, three- 

 ranked on all the upper whorls, four on the body-whorl, is of a 

 graceful shape and fairly sized. It is unfortunate that all the 

 specimens we have examined are without the apical whorls. 



Triforis perversus L. 



P.G. Bushire. 



I. Bombay {Abercrombie). 



We cannot distinguish the Bushire and Bombay specimens from 

 the Mediterranean shell. The Triforides (especially acutus) are 

 amongst the most plentiful small mollusca dredged at a few fathoms' 

 depth. 



1 Idoneus, suitable. 



