MACTRA. 133 



Mactra plicataria. Linnaus Syst. Nat. p. 1125. Chemnitz, 

 vi. p. 213. t. 20. f. 202 to 204. Schroeter Einl. iii. p. 

 73. Gmelin, p. 3237. 



Inhabits the coasts of Java. Linnceus. Tranquebar. Chemnitz. 



Shell about two inches long, two inches and three-quarters 

 broad, and one inch high; of a pale, dull, brownish white 

 colour, and strongly plaited transversely, both inside and 

 out; the hinge is placed considerably nearer the anterior 

 than the posterior end, and has parallel membranes in th« 

 room of lateral teeth. 



papyracea. 3. Shell somewhat triangular, ventri- 

 cose, transversely plaited, diaphanous, and 

 very brittle ; anterior margin slightly re- 

 flected. 



Mactra papyracea. Chemnitz, vi. p. 233. t. 23. f. 231. 

 Gmelin, p. 3257. 



Mactra, No. 9. Schroeter Einl. iii. p. 84. 

 Inhabits the coasts of the Nicobar Islands. Chemnitz. 

 Shell about nine lines long, and thirteen broad, extremely 



brittle, pellucid, and white, and resembles M. plicataria, 



but is much smaller, more convex, and more inequilateral ; 



it is striated, and plaited transversely, and the valves do not 



close at the anterior end ; except in the hinge, it is said 



much to resemble a Tellina. 



vitrea. 4. Shell somewhat heart-shaped, diaphan- 

 ous, very brittle, and transversely plaited ; 

 anterior depression lanceolate, and the pos- 

 terior ovate-oblong. 



Mactra vitrea. Chemnitz, xi. p. 219. t. 200. f. 1959 and 

 I960. 

 Inhabits the coasts of Coromandel and Ceylon. Chemnitz. 

 Shell about eleven lines long, and thirteen broad, and appears 



in all respects to be very nearly allied to M. papyracea. 



itriatula. 5. Shell smooth, with the anterior 

 slope depressed in the middle, and keeled at 

 the margins, and the posterior end produced. 



Mactra striatula. Linnaus Syst. Nat. p. 1125. Chemnitz, 

 vi. p. 215. t. 21. f. 205 and 206. Schroeter Einl. iii. p. 

 73. Gmelin, p. 3257. 



Mactra Spengleri. Born. Mus. p. 51. 



