C YTH ERE A. 



Plate V. 



Species 15. (Mus. Cuming.) 



Cythf.rea laevigata. Cuth. tesld ovato-tnijond, subaqui- 

 laterali, teimicidd, hitcscenfe-alhd, vlolnceo iinctd et 

 concent rice fasciatd, umbonibus violaceis, lavhjntd, ni- 

 tei ■ 



The smooth Cytherea. Shell ovately triangular, nearly 

 equilateral, rather thin, yellowish- white, tinged and 

 concentrically banded with violet, uniboes violet, 

 smooth, shining. 



Triffona Icevigata, Gray, Cat. Cyth. Anal. vol. viii. p. 30-t. 



Hub. ■ ? 



A delicate species, of nearly equilateral triangular form. 



Species 16. (Fig. ", b, !Mus. Cuming.) 

 Cytheuea tripla. Cylli. testd trigono-cuneiformi, viedio 

 ff/bbosd, uirinque peculiariter late compressd, sordide 

 flaveacenie-albd, nunc wurantio tinctd, interdmn cinereo- 

 griseo radiatd, soUdd, lavigatd, vel dense concentrice 

 striata, areis laleralibus late excavatis. 

 The triple Cytherea. Shell triangularly wedge-shaped, 

 gibbous in the middle, peculiarly broadly compressed 

 on each side, dull yellowish-white, sometimes tinged 

 with orange, sometimes rayed with ash-grey, solid, 

 smooth or densely concentrically striated, lateral areas 

 broadly excavated. 

 Venvs tripla, Linnaeus, Mant. p. 545. 

 Cytherea tripla, Lamarck. 

 Trigoua tripla. Gray. 

 . Senegal. 

 \ solid triangular shell, extremely varied in colour, 

 " aving the lunule and ligament areas pinched, as it were, 

 into broad excavations. 



bosissit/id, griseo-albd, epidermide corned fnlvd partini 

 indntd, latere antico inimerso, latere postico orcuato, 

 late abrupte truncato, area ligamenti perampld, ex- 

 cavatd. 



The ventricose Cytherea. Shell cordately triangular, 

 very gibbous, greyish-white, partially covered with a 

 fulvous horny epidermis, anterior side immersed, pos- 

 terior side arched, broadly abru])tly truncated, liga- 

 mentary area very large, excavated. 



Trigona ventricosa, Gray, Cat. Cyth. Anal. vol. viii. p. 30-t. 

 Cgtherea ventricom, Sowerby. 



Ilah. China. 



This fine species is the most gibbous and abruptly trun- 

 cated of the genus, and none of similar type approaches it 

 in size. 



Species 17. (Mus. Cuming.) 

 Cytherea ventricosa. Cyth. testd cordato-trigond, gib- 



Specics 18. (Fig. a, b, c, Mus. Cuming.) 



Cytherea Mactroides. Cglh. testd trigond, ventricosa, 

 sitbieqiiilaterali, utrinqne subcompressd, albidd, rnfes- 

 cenle-castaneo plus minus iinctd et radiatd, epider- 

 mide corned f aha interdum partim indutd, lavigatd. 



The Mactra-like Cytherea. Shell triangular, ven- 

 tricose, nearly equilateral, rather compressed on each 

 side, whitish, more or less rayed and stained with 

 reddish-chestnut, sometimes partially covered with a 

 fulvous horny epidermis, smooth. 



Venus Mactroides, Born, Test. Mus. Vind. 

 Venus coriicula, Gmelin. 

 Cytherea corbicula, Lamarck. 

 Trigona corbicula. Gray. 

 Trigona Mactroides, Deshayes. 



Hab. West Indies. 



The colouring is mostly reddish-chestnut, though ex- 

 tremely variable in design. The lateral areas are rather 

 broader than in C. radiata and other allied species. 



Januarv, 18G4. 



