﻿C Y R E N A. 



Plate VII. 



Division, Cyrena proper. Anterior lateral tuutli 

 short, not serrated. 



Species 22. (Mns. Brit.) 

 Cyrkna Papl'A. Oyr. testa ovatd, compressd, stramined, 

 concenlnce S7ihdii!tanfer fimbriatim striatd ; vomus 

 nmhones utrhique area )'h7^))ys.«(" uinr^iiiinfi' : Infi^rc 

 finticn bri'vi, rotundo, mai-iji,:' ,L>r^,ii; ,n,ir,:n'i, 

 declivi ; latere jxisticci produrlu, rudinlnii n ii'jnlntil, 

 mill-glue dursali jirujir iniihoHes conve.w, tihii de- 

 cliri, marijiiie frnniinih' breviter trmicato; nm- 



TiiE Papua Cykena. Shell ovate, compressed, straw- 

 coloured, concentrically rather distantly fringe- 

 striated ; bordered on each side near the umboes 

 with an impressed area ; anterior side short, 

 I'oand, dorsal margin convex, sloped downwards ; 

 posterior side produced, radiately angular, dorsal 

 margin convex near the umboes, then sloped 

 downwards, terminal margin shortly truncated ; 

 umboes depressed. 



Lesson. Guerin : Mag. Zool. PI. XI. 



Hab. ? 



Species 23. (Mus. Brit.) 



Ctkena Bengalensis. Cyr. tes'd solidd, tumidd, 

 cntSKil, mhtrigondffasco-niijrescenti, rwjoso-striatd; 



Int.- 



d;o,alinl.rrns.!,u,Kd,,-j:n,,uiii,h; late 



t;.;. ,rud,n-t.. 



.,.■ .l.,:<.,i: I..,,.,; decliri, ad 

 trniiiiiiiiii fruiiriiln^ inifr miijiihuii n'.r r.iravato. 



The Bknc.al Cyuena. Shell solid, tumid, thick, 

 subtrigonal, blackish-brown, roughly striated ; 

 anterior side high, very short, sloped, full; pos- 

 , terior side produced, dorsal margin with a long 

 slope, truncated at the end, very slightly ex- 

 cavated in front of the angle. 



Lamarck. Anim. sans Vert. Cyreua, 10. 



Hab. Bengal. 



fcpecies 21. (Mus. Brit.) 

 Cyresa Cypeinoides. Gi/r. testa magnd, aUis.^imd, 

 ivtundo-subquadrald, subviride fused, nnjuso- 

 I'trlatd ; latere aiitico brevi.'isiiiio, subtus umliunes 

 v.ccaoaio, area, svhhnndari imj^iresso; unibouibus 

 iaiMrcis, fere teniinHilihns ; latere postico sub- 

 •liiadralo, radiat'uio ni/j'nu.-iii, margine dursali 

 iiiniiato, iiinrgine tenuiiialt "iiiKuio. 



The Cyprina-like Cyrena. Shell large, very liij^li. 

 roundly subquadrate, greenish-Iirown, ronglily 

 sti-iated ; anterior side very short, excavated 

 under the umboes, impressed with a lunnle-like 

 area ; umboes incurved, nearly terminal ; pos- 

 terior side rather square, radiately impressed, 

 dorsal margin arched, terminal margin sinuous. 



Guoy. Voyage de I'Astrolabe. PL LXXXII. f. 1-;;. 



Hah. ? 



Species 2.j. C^lus. Brit.j 



CyRENA TRIANlJULAinS. Gljr. tl'ntd Iriijnild, 'lltUsillld, 



coniirressd, concentrich temiiter, lainiUe undatiiii 

 striata ; latere antico brevissimo, versus marginem 

 ventralem acummatiin produetu, subtus mnbones 

 subexcavato, fere perpendiculariter dedivi ; um- 

 boiiibiis altisslmis ; latere postico versus marginem 

 radiatiin impresso, man/iin: tcruiiiint! .<i'bfniiicatii, 

 iiiargliie dorsali hmge iirri',ilii,i '/■■cliri. 



The triangular CyRENA. Shell trig.jtial, very high, 

 compressed, concentrically tiuely, minutely, 

 wavily striated ; anterior side very short, acu- 

 minately produced towards the ventral margin, 

 somewhat excavated under the umboes, almost 

 perpendicularly sloped ; umboes very high ; 

 posterior side radiately impressed not far from the 

 margin, dorsal margin with a long, arched slope. 



Metcalfe. MS. Cum Coll. 



Hah. ? 



Species 26. (Mus. Brit.) 



Cyrena sinuosa. Cyr. testa subquadratd, altiiisculd, 

 pmnderosd, epidermide fusco-nigreseentl rugoso- 

 striatd indutd; latere antico brevi, infra sub- 

 rotunda ; umbonibus fere termiiialibus ; latere 

 2>ostico producto, subquadrate, sulds duobus 

 siiuiatis radiatim impressd, margine termiiiali 

 sinuato, margine dorsali arcuatim declivi. 



The sinuous Cyrena. Shell .subquadrate, rather 

 high, ponderous, covered with a blackish-brown 

 roughly-striated epidermis ; anterior side short, 

 roundish below, umboes nearly terminal ; pos- 

 terior side produced, rather square, radiately im- 

 pressed with two sinuated grooves, terminal mar- 

 gin sinuous, dorsal margin sloped with a curve. 



Deshayes. Proc. Zool. Soc. 185 i, p. 18. 



Hah. Ueylon. 



