DIONE. 



Plate VIII. 



Species 30. (Mus. Cuming.) 



DiONE AFFlNls. Bion. testd ovato-ohlowjd, obtuse iri- 

 anyulari, suhcompressd, alba, purpureo-violaceo ra- 

 diatd, lunula et ared ligamenli violaceis, conceiitrice 

 liratd, liris subre/lexis, hie illic corruffatis, latere 

 posticojlexuoso. 



The allied Dione. Shell ovately oblong, obtusely 

 triangular, rather compressed, white, rayed with pur- 

 ple-violet, lunule and ligauientary area violet, con- 

 centrically ridged, ridges slightly reflected, hei'e and 

 there wrinkled, posterior side flexuous. 



Ci/therea offiiiis, Broderip, Pro. Zool. Soc. 1S~5, p. 4.5. 

 Venus Payteusis, D'Orbigny. 

 Dione affinis, Deshayes. 



Ilab. Xipixapi, West Cohunbia ; Cuming. 



Scarcely distinguishable from the next species except in 



being rather more flexuously compressed on the ])osterior 



side, and in having the luuule and ligamentary area violet. 



Species 31. (Fig. a, b, Mus, Cuming.) 



Dione concinna. Dion, testa oUongo-cordatd, sub- 

 conipressd, caslaneo-rufd vel alba, purpnreo-roseo 

 radiatd, coneeutrice liratd, liris siihrejie.vis, hie iUic 

 corrugatis, latere postico subjlexnoso. 



The elegant Dioxe. Shell oblong heart-shaped, rather 

 compressed, chestnut-red or white, rayed with purple 

 rows, concentrically ridged, ridges slightly reflected, 

 here and there wrinkled, posterior side a little 

 flexuous. 



Cytherca concinna, Sowerby, Pro. Zool. Soc. 1835, p. 23. 

 Dione concinna, Deshayes. 



Hub. Panama, Mazatlan. 



The details of sculpture are precisely the same iu this 

 as in the preceding species. 



Species 32. (Mus. Cuming.) 



Dione purpueata. Dion, testd rotundato-cordatd, crassd, 

 violaceo-purpured, palli.de fasciatd, marginibns albis, 

 Itecigatd, concenlrice irregnlariler plicuto-sulcatd. 



The pcrple Dione. Shell rotundately heart-shaped, 



thick, violet-purple, ]iale banded, margins white, 

 smooth, concentrically irregidarly plicately grooved. 



Lamarck, Anim. sans vert. vol. vi. p. 301. 



Hab. ? 



A tine solid porcelain-like shell, distinguished by a 

 charming tone of colour. 



Species 33. (Pig. a, b, Mus. Cuming.) 



Dione unicolor. Dion, testa trigono-cordatd, subcom- 

 pressd, crassd, albidd tel custaneo-spadiced, concen- 

 lrice liratd, liris subobtusis, hie illic corrugatis, ver- 

 sus latus posticum iuterdum obsoletis. 



The one-coloured Dione. Shell triang\darly heart- 

 shaped, rather compressed, thick, whitish or chest- 

 nut-bay, concentrically ridged, ridges rather obtuse, 

 here and there wrinkled, sometimes partially obso- 

 lete towards the posterior side. 



Cjjtherea unicolor, Sowerby, Pro. Zool. Soc. 1835, p. 23. 

 Chione badia. Gray. 

 Cytherea ligula, Anton. 

 Dione unicolor, Deshayes. 



Ilab. West Columbia. 



There is a tinge of the characteristic chestnut-bay 

 colouring of this species in the pale variety of it. 



Species B-i. (Mus. Cuming.) 



Dione cyonus. Dion, testd trigono-oblongd, subcordatd, 

 postice oblique productd, calcareo-albd, concenlrice 

 liratis, liris lamellatis, pracijme ad latus anlicmn, 

 crenntalis et exasperutis. 



The swan Dione. Shell triangularly oblong, somewhat 

 heart-shaped, posteriorly obliquely produced, chalk- 

 white, concentrically ridged, ridges lamellate, espe- 

 cially on the anterior side, crenulated, and broken. 



Cyiherea cygnus, Lamarck, Anim. sans vert. vol. vi. p. 328. 

 Dione cygnus, Deshayes, 



Hab. ? 



A dead-white shell, in which the ridges are finely cre- 

 nulated, and more or less broken. 



August, 18G3. 



