631 



65. Cyther^a ciRCiNATA (pi. cxxxii. f. 104, 105, 106), 

 Born, Mus. t. 4. f. 8. Venus rubra, Gmel. 3288 ? C. alternata, 

 Broderip, Pro. Zool. Soc. 1835. p. 45. 



Cyth. testa ovali-subrotundata, ventricosa, alta, alba rubro-ra- 

 diata seu orauino purpurea ; laminis erectis, acutimarginatis, in 

 medio numerosis, ad latera distantioribus, productioribus, concen- 

 trice costata ; margine dorsali plerumque purpureo ; lunula dis- 

 tincta, plerumque purpurea. 



Shell rather rounded, ventricose, with laminar ribs, which are 

 less numerous and broader at the sides, particularly at the ante- 

 rior, white, with purple rays, or entirely purple, generally with 

 the dorsal margin and lunule of a darker purple. The ribs are 

 unequal, and in the variety named C. alternata by Broderip, every 

 alternate one dies out near the sides, the other being more 

 expanded. 



Mazatlan, Bonnet, R.N. Var. C. alternata, fig. 104, West 

 Columbia ; dredged in sandy mud at fifteen fathoms. Cuming. 



66. CYTHERiEA CYGNUS (pi. cxxxii. f. 107), LamaTck, Anim. 

 s. vert. Cyth. no. 77. 



Cyth. testa alba, C. circinatce simili, sed umbonibus ventricosis, 

 elevatis ; margine dorsali retuso, subplauulato ; lunula magna, 

 cordiformi, distincta, impressa. 



Shell more ventricose, with larger and more elevated umboes 

 than C. circinata ; the posterior dorsal margin retuse ; the lunule 

 large and distinct. 



Locality unknown. Mm. Cuming. 



67. CYTHERiEA DiONE (pi. cxxxii. f. 110), LinncBus, Syst. 

 Nat. p. 1128. 



Cyth. testa ovali, subventricosa, alba, violaceo tincta, laminis 

 elevatis acutis usque ad angulum cincta, postice subelongata, angu- 

 lata, ad angulum spinis elongatiusculis ornata, post angulum vix 

 striata; prope umbonem serie altera spinarum breviuscularum ; 

 margine dorsali declivi, subinflata, nonnunquam rosea; lunula 

 parva, nonnunquam rosea, distincta ; latere antico laminis alteris 

 evanidis, alteris expansis. 



Shell oval, with two rows of spines at the hinder side, one at 

 the angle with the spines long, the other behind, near the um- 

 bones, with the spines shorter ; laminEe erect and sharp-edged, some 

 reaching to the front as far as the edge of the lunule, where they 

 are much expanded, others terminating sooner. 



Venezuela and Trinidad. 



