Zoological Society. 509 



more obtuse hinder extremity, and the greater convexity and less 

 sudden slope of the dorsal edges, suffice for its separation. 



Tellixa robusta. Tel. testa parvd, rotufidato-subtrigond, solidd, 

 subincequivalvi, subcequilaterali, ventricosd, nitidd, aitt albo-flaves- 

 cente, aut pallide rosaced, sMcEvigatd {plenimque inferius remote 

 substriatd) ; margine vent rati valde arcuato, dorsali utrinqve sub- 

 recto et valde declivi ; latere postico attenuate, fere subrostrato, 

 ad extremitatem acuminata ; Ugamento angustissimo, infosso ; na- 

 tibus distinctis, prominentibus, et rede incurvatis ; timbonibus 

 tumidis ; flexurd distinctd ; casta umbonali fere obsaletd ; lunuld 

 parvd; superficie internd, plerumque sub umbanibus, flavidd aut 

 rosed ; dentibus ut in T. nuce. Long. 0'70 ; lat. O'SO poU. 

 Hab. Isle of Annaa, South Seas, and isle of Burias, Philippines ; 

 sandy mud, low water. 



Is closely allied to mix, jjinguis and casta, but of a stouter tex- 

 ture even in the youngest individuals. The ligamental edge being 

 nearly straight, easily separates it from pinguis, where it is decidedly 

 convex. 



Tellixa casta. Tel. testd obavali, tenuissimd, subinccquivalvi, 

 subcequilaterali, pellucidd, convexd, nitidd, extus intusque candidd, 

 leevigatd ; margine ventrali maxime arcuato ; dorsali ufrinque sub- 

 recta, suhccqualiter satisque declivi; extremitate posticd angustd, 

 biangulatd ; Ugamento angustissimo, subinfosso ; natibus acutis ; 

 flexurd ventrali costdque umbonali distinctis ; dentibus ut in T. 

 nuce. Long. 036 ; lat. 048 poll. 



Hab. Singapore ; sandy mud. 



Bears some resemblance to T. nux, but the shape is less broad, 

 the ventral edge decidedly arcuated, the dorsal edges less convex and 

 shorter, and the umbones colourless. 



Tellina Discus. Tel. testd T. Remiei simillimd, sed subobliqud et 

 sulcis concentricis valde irregularibus, vixque continuis ; natibus 

 hand recte incurvatis; margine j^ostico dorsali elevatiore, antico 

 dorsali, prope 7iates prominulas subincurvato ; tinibonibus Itevi- 

 gatis ; extremitate posticd angulatu. Long. 2' 75 ; lat. 3 poll. 



Hab. Isle of Mindanao ; on reefs, in coarse sand. 



Tellina ctrenoidea. Tel. testd suborbiculari , soUdiusculd , in- 

 aquivalvi, valde inaquilaterali, subventricosd, sordide albd (intus, 

 sub umbanibus, purpured), concentrice costellatd ; striis minutis 

 oblique radiantibus, castellas confertas jyastice decussantibus ; 

 margine ventrali arcuato ; dorsali utrinque valde et subrecte declivi, 

 antice brevi, postice langiore ; latere antico breviore, obtuse rotun- 

 dato ; extremitate posticd obtusd, paululiim attenuatd; natibus 

 prominentibus ; lunuld distiiictd ; Ugamento infosso ; flexurd cos- 

 tdque umbonali obsoletissitnis ; dentibus lateralibus parvis, distinc- 

 tis, subcequidistantibus. Long. 0'60; lat. 0"70. 



Hab. St. Nicholas, isle of Zebu ; sandy mud, low water. 



In external appearance bears much resemblance to a Cyrena. 



