﻿C Y K E N A. 



Plate XI. 

 (Species 42 iiiadvei-tently omitted.) 



Species 43. (^rus. Brit.) 



CtRENA TEIGONA. Cl/r. tentd oni'n, .<iiJ,l,!,iijii;hilfriiVi, 

 siriimiiied, concentrice teiiiiil, r stmil.!: Iff, rr /■<,.<. 

 tico mnjiiri, subarcxiaiim ih-clivi, 2'i'"i"-' iinii'i/'iiiin 

 angulato, viaryine ventrall caiivexo; latere antico 

 suhacuminato, umbantbus veisus marginem anii- 

 cum indiiiatis ; viargine antico valde declivi. 



The trigonal Cyrena. Shell ovate, rather inequi- 

 lateral, straw-coloured, concentrically fiuelj' 

 striated ; posterior side the larger, sloped in a 

 slight curve, angular near the margin, ventral 

 margin convex ; anterior side slightly acumi- 

 nated, nmboes inclined tovfards the anterior 

 margin, anterior margin miioh sloped. 



Deshates. Proc. Zool. Soc. 1854, p. 344. Hanley, 

 Conch. Ind. PI. 155. 



Hub. Pondiclicrry. 



This is given on the anthority of the British 

 Museum (as type) and the Conch. Ind., but the shell 

 is far from being t>f a trigonal form. 



Species 44. (Mns. Brit.) 



Cyrena Bex.-joni. O/r. tc'ifi! .■^•uhoratd, suhc.ompref/td, 

 stnuiiiii'i!, t' iinissiiiir rmliufi!, t, ninter undulatiia 

 cinri-iilricr nni,i',i^ Hfinii 'il< rali : latere antico 

 jinijii' iiiiirqinnn iitninhil,! : I'tfi ri' 2JO.<tieo angulato, 

 ad auijuhiiti <Unirii-iiti m ruijatd; umboiiihiis ccn- 

 iralibiis ii,tii.< r.rh'i^quo rnhrix. 



Benson's Cyrkna. Shell subovate, subcompressed, 

 straw-coloured, very iinely rayed, wrinkled with 

 fine concentric undulations, equilateral ; anterior 

 side angulated near the margin ; posterior side 

 angular, divergently wrinkled at the angle ; 

 nmboes central, red inside and out. 



Deshayes. Proc. Zool. Soc. 187b, p. 345. 



Hab. River Jumna. 



Said to be notable for its general smoothness. 



To the -WTiter it appears most remarkable for the 



acutely angular diverging wrinkles on the posterior 



angle. 



Species 45. (]\lus. Hanley). 



Cyrena Iravadica. Cijr. testd triijono-snlovatd, nltd, 

 ventricosd, concentrice yrnfiuidh rugatd, ad imi- 

 bones cccrulcd ; infra olivaced, intils purpurrd, 

 umbonibus subccutralibns, elcvatis, margine dorsali 

 utrinque de.clivi; margine reidrali validii convejM. 



The Irawaddy Cykena. Shell trigono-subovate, 

 elevated, ventricose, concentrically deeply i-ugose, 

 blue at the umboes, olivaceous below, purple 

 within ; umboes nearly central, raised, dorsal 

 margin sloped on each side ; ventral margin very 

 convex. 



Bi.ANDFOKD. MS. Hanley. Conch. Ind. PI. 155. 



Uab. River Irawaddy, Pegu, Ava. 



Species 4G. (F. a, b, Mns. Sowcrby.) 



Cyrena erosa. Cyr. testd altissimd, solidiiisculd, sub- 

 wijuilaterali, trigond; inti'is omnino, prope mar- 

 ijinem dansissime purpuratd, dentibus lateralilius 

 elongatis, serratis, cardinalibus tribm, elongatis ; 

 latere antico breviiuscido, ared semilwnatd,planulatd, 

 lati-re postico infra subprodiicto, umbonibus deva- 

 tinsimis; liris concentricis distantibns, tenuibus. 



The triangular Ctre.n'A. Shell very high, rather 

 solid, subequilateral, trigonal, purpled within all 

 over, very deeply near the margin : lateral teeth 

 elongated, serrated ; cardinal three ; anterior side 

 rather short, with a semilunar, flattened area ; 

 posterior side a little produced below, umboes 

 much raised ; concentric ridges distant, thin. 



Deshayes. MS. Proc. Zool. 1854, p. 354. 



C[irena triangularis. Deshayes ? 



Eah. ? 



Species 47. (a, b, Mus. Sowerby.) 

 Cykena radiata. Cgr. testd alld, olliipte subtrigond, 

 tamidd, regnlariter subdistanter liratd, inti'(s 

 utrinque radlatim pnrpiireo-fasciatd ; latere antico 

 hreviiisculo, ared depressd, lunulari ; latere postico 

 oblique pauli) producto, radiatim angrdato ; m«i- 

 bonibus elevatis, acuminatis, marginibus lateralilius 

 declivibus. 



