DIONE.— Plate I. 



The Erycina Dione. Shell somewhat cordately ovnte, 

 very inequilateral, rather thick, fawn-brown, stained 

 with orange-red towards the margin, interruptedly 

 rayed \vith chocolate-brown, concentrically linearly 

 grooved throughout. 



Venus Erycina, Linnaeus, Syst. Nat. p. 1131. 

 Cytlieri'a Erycina, Lamarck. 

 Okione Erycina, Gray. 

 Bionc Erycina, Deshayes. 



Hub. Indian Ocean. 



This very common species is quite remarkable for the 

 richness and brilliancy of its colouring. 



Species 4. (Fig. a, h, Mus. Cuming.) 



I'lOXE ChinensIs. Bion. ledd sulohliiine ovutd, jmstice 

 SHhattenuatd, depresm, spadiced, viulaceo vel f/is- 

 ccKcei/te varii radiatd ct fasciatd, jrrascriim versus 

 ■niarrjinevt, latere anlico concentrice Utieari-siilcato. 



The China Dione. Shell rather obliquely ovate, pos- 

 teriorly somewhat attenuated, depressed, fawn-co- 

 lo\u-ed, variously rayed and banded with violet or 

 light-brown, especially towards the margin, anterior 

 side concentrically linearly grooved. 



I'einis Chinensis, Chemnitz, Conch, vol. ii. p. 227. pi. 202. 

 f. I'JTfi. 



Cytherea Sinensis, Sowerby. 

 Hab. China Seas ; New Holland. 



Very closely allied to B. fesliva, but moi-e depressed 

 and more attenuated posteriorly. 



Species 5. (Mus. Cuming.) 



Dione lilacika. Bion. testd subcordalo-ovatd, valde 

 inaqullaterali, postice subattenuold, spadiceo-fusces- 

 cente, obscure Uneari-radiatd, versus ■iiiargineiii lila- 

 cind, concentrice vndiqne lineari-sidcatd, costis iuter- 

 mediis courexiiiscnUs. 



The lilac Dione. Shell somewhat covdateiy ovate, 

 very inequilateral, posteriorly rather attenuated, fawn- 

 brown, obscurely linearly rayed, stained towards the 

 margin with lilac, concentrically linearly grooved 

 throughout, the intermediate ribs rather convex. 



Cytherea lilacina, Lamarck, Anim. sans vert. vol. vi. 

 p. 303. 



Chione lilacina. Gray. 

 Bione lilacina, Deshayes. 



Hab. Australia. 



Coloured towards the margin with a \ery peculiar tone 

 of lilac. 



