﻿C Y E E N A, 



Plate II. 



Species 3. (Mns. Brit.) 



CvKEN.\ TKIQHETRA. Cijr. testa suhtrigond, alia, mh- 

 cmiqjressd, Icevl, epidennide suhvlridi, partim 

 nigrescenti ituliitd; latere antico brevissimo, de- 

 clivi ; umhonihus elevatis ; latere posticn angulato, 

 margiite dorsali declivi. 



The thkee-cornered Cybena. Shell rather trigonal, 

 high, rather flat, smooth, covered with a rather 

 green epidermis, blackish in parts ; anterior 

 side very short, sloped ; umboes raised ; pos- 

 terior side angular, dorsal margin sloped. 



Deshayes. Proc. Zool. Soc. 1854, p. lo. 



Hab. Philippines. 



Species 4. (Mns. Brit.) 



Cyrena rotitndata. Cgr. testa rotinidd, tumidd, in- 

 CBquilateraU, irregulariter rugatd et sidcatd, epi- 

 dermide solidd, subviridi, nitenti, medio radiatim 

 striata, indiitd ; intth sparsim violascenti ; latere 

 antico brevi, compresso ; latere postico iumidissimo, 

 snblmvigato, margine laterali subqiMdrato. 



The rounded Cyrena. Shell round, tnmid, inequi- 

 lateral, irregularly wrinkled and grooved, 

 covered with a solid, greenish, shining epi- 

 dermis, radiately striated in the middle; 

 sparingly purpled within ; anterior side short, 

 compressed ; posterior area very tumid, rather 

 smooth, lateral margin rather square. 



Lea. Trans. Am. Ph. Soc. PI. XVII. f. 51. 



Hah. East Indies. 



More tumid in the middle, and more depressed at 

 the dorsal margin than Cyrena lentlcularis. \ 



Species 5. (Mus. Brit.) 



Ctrena OBEsa. Cyr. testd subovatd, la-vigald, castaned, 

 tumidd, distanter leviter sulcata ; latere antico 

 brevi, tenuiler rugato, declivi; latere postico 

 obscure triangulato ; margine dorsali recliiisculo. 



The pat Cyrena. Shell subovate, smooth, chestnut, 

 tumid, distantly slightly grooved ; anterior side 

 short, finely wrinkled, sloped ; posterior side 

 obscurely three-angled ; dorsal margin rather 

 straight. 



Hinds. Voy. Sulphur. 



Hab. Feejee Islands. 



The posterior side is much produced, and the margin 



modified in shape by the three radiating obsure angles. 



Species (5. (Mus. Brit.) 



Cyrena Keraudreni. Cyr. testd magna, crassd, ,<«i- 

 ovatd, postice distanter, antice crebre sidcatd, epi- 

 dermide nigra indutd ; intus margine cardinali 

 postico purpurea maculato, medio subradiatu, 

 latere antico brevi, declivi ; latere postico produclu, 

 subactiminato, ligamento mamimo, elongato. 



Keraudren's Cyeena. Shell large, thick, subovate, 

 posteriorly distantly, anteriorly closely sulcated ; 

 covered with a black epidermis ; with a purple 

 spot on the posterior cardinal margin within, 

 somewhat rayed in the middle ; anterior side 

 short, sloped ; posterior side produced, a little 

 acuminated, ligament very large, long. 



Lesson. Voy. de la Coquille. PI. II. f. 3. 



Hah. Philippines. 



Has very much the form and appearance uf a 



large dark Cyprina. 



