DIO N E 



Plate I. 



Genus DIONE, Megerle. 



Testa ovafn, tnryidiiiscida, nunc subincrasmia, Scepissiiiii 

 concentrice cuslata, nunc tenuis, l/Tvlgata, valde in- 

 irquilateralis, marriinibns intei/ris. Cardo iti vtrnqiie 

 valvd trideritatiis, dmtibus vix dherijentihus. Ini- 

 pressio pallii postice siiiiiatiis, siiin sitliprofuiido. 



Shell ovate, rather swollen, sometimes rather thick, and 

 mostly concentrically ribbed, sonietiiiies thin and 

 smooth, very inec|uilateral, margins entire. Hinge in 

 each valve three-toothed, teeth scarcely divergent. 

 Impression of the mantle sinunted posteriorlv. sinus 

 rather deep. 



Two very distinct forms, represented respectively by 

 the Linnsean Venus Erycina and V. Ireta, are referred to 

 the genus Diorie, even by those who have subdivided the 

 family of Venerida into more genera than it has been 

 deemed advisable to adopt in this work. In the first of 

 these groups the shells are large, sometimes smooth and 

 highly polished, sometimes concentrically ribbed, and all 

 more or less consjiieuous for their brilliancv of colouring ; 

 in the second the siiell is thin, inflated, and almost colour- 

 less. The most remarkable sjjecies are a group, of wliieh 

 D. Feneris is the type, inhabiting Central America and 

 the West Indies, in which the concentric ridges are pro- 

 longed on the posterior angle of the shell into spines. 



The general distribution oi Dioneis, the same as tliat of 

 Venus, though not half so numerous in species. Central 

 America, the Philippine Islands, and Australia are the 

 principal places of habitation. There are, however, three 

 important species, B. Hagenowi, jiorida, and umbonella, 

 from the Red Sea, and we have a remarkably fine species 

 for so northern a latitude as our own in B. Chione. I), um- 

 bonella is quoted as being a native also of Brazil ; and 

 another instance is presented of the same species being 

 found in both hemispheres in B. squdlida, which was cer- 

 tainly collected by Mr. Cuming at the Pliilippine Islands, 

 and is reported to inhabit California also. 



Species 1. (Fig. 1 a, b, ^lus. Cuming.) 



DiONE FLORID.^. Bion. leslii ovntii, versus matyinem coui- 

 pressiusculd, laded vet clnered, fulvo-fuscescenle pJe- 

 rumque minute undatd el variegutd, versus marginem 

 nigricante-violuceo conspicm late radiatd, latere pos- 



lico oblique producto, antico concentrice tineari-snlcato, 

 snlcis subdistantibus, lunula niyricante-violaced, area 

 tigamenti nitide strigatu. 



The ELORlD DiONE. Shell ovate, rather compressed 

 towards the margin, cream-coloured, or ash, generally 

 minutely waved and variegated with fulvous-brown, 

 conspicuously broadly rayed towards the margin with 

 dark-violet, posterior side obliquely produced, an- 

 terior side concentrically linearly grooved, grooves 

 rather distant, lumde dark-violet, ligamentary area 

 neatly streaked. 



Cgtherea Jiorida, Lamarck, Anim. sans vert. vol. vi. p. 305. 

 Cijtherea pulchra, (iray. 

 Chione pulclrra. Gray. 

 Cylherea ErycineUu, Lamaixk. 

 Bione Jiorida, Deshayes. 



Hub. Ked Sea. 



This very pretty species is sculptured in a very charac- 

 teristic manner on the anterior side by a series of rather 

 distant concentric linear grooves, the posterior being 

 smooth. 



Species 3. (JIus. Cuming.) 



DiONE FEST1V.\. Dion, testa suboblongo-ovatd, postice 

 subattennatd, solidiusculd, fulvescente-spadiced, vio- 

 laceo-roseo radiatd et fasciatd, latere antico concen- 

 trice lineari-sulcato. 



The pretty Dione. Shell rather oblong-ovate, poste- 

 riorly a little attenuated, rather solid, fulvous-fawn, 

 rayed and banded with violet-pink, anterior side con- 

 centrically linearly grooved. 



Cylherea festiva, Sowerby, Thes. Conch, vol. ii. p. 62.5. 

 pi. 130. f. 72. 

 Bione festiva, Deshayes. 



Hab. Eastern Seas. 



(^nspicuously distinguished by its pretty violet-rose 

 colouring. 



Species 3. (Mus. Cuming.) 



Dione Erycina. Dion, testd subcordalo-ovatd, valde in- 

 aquilaterali, cra-isiusculd, spadiceo-fuscd, versus mar- 

 ginem auruntio-rufo tinctd, chocolalo-fusco inlerru ti 

 radiatd, concentrice iindique lineari-sulcatd. 



February, 1864. 



