MACTRA. 135 



Mactra, No. 3. Schroeter Einl. iii. p. 81. 



Inhabits the coasts of Tranquebar. Chemnitz. 



Shell about two inches long, and two inches and a half broad, 

 and sometimes considerably larger ; thin, pellucid, of a pale 

 ochraceous colour, finely striated transversely, and wrinkled 

 at the two ends ; the inside is finely striated longitudinally, 

 and is white, with a large purple spot under the hinge ; the 

 hinge has a double complicated intermediate tooth, and la- 

 teral membranes. 



violacea. 9. Shell diaphanous, violet, finely stri- 

 ated transversely, and the inside longitudi- 

 nally ; anterior slope lanceolate, and the pos- 

 terior oblong. 



Mactra violacea. Chemnitz, vi. p. 220. t. 22. f. 213 and 



214. Gmelin, p. 3260. Solanders MSS. Portland 



Cat. p. 9- lot 185. ? 

 Mactra, No. 4. Schroeter Einl. iii. p. 82. 

 Variety. Shell stronger, and the umbones only of a violet 



colour. 

 Mactra violacea australis. Chemnitz, xi. p. 217- t. 200. f. 



1954. 

 Inhabits the coasts of Tranquebar. Chemnitz. 

 Shell two inches and a quarter long, and three inches broad ; 

 thin, smooth, somewhat pellucid, very finely striated trans- 

 versely on the outer surface, and the inside longitudinally ; 

 the colour both inside and out is violet, forming paler and 

 darker irregular concentric zones ; the hinge resembles that 

 of M. turgida. Chemnitz's fig. 1954, represents a shell 

 three inches long, and four inches broad, and may probably 

 prove to be M. rotwidata, in a more advanced stage of 

 growth ; he says it inhabits the coasts of China, and the 

 South Seas. 



cuneata. 10. Shell wedge-shaped, violet, finely 

 striated transversely, and the anterior end 

 truncated ; margin acute, and crenulated 

 within. 



Mactra cuneata. Chemnitz, vi. p. 221. t. 22. f. 215. Gme- 

 lin, p. 3260. 

 Mactra, No. 5. Schroeter Einl. iii. p. 83. 

 Em. Method, t. 257. f. 5. 



