NATURAL SCIENCES OP PHILADELPHIA. 219 



M. ovum, Gray. 



Pholas ovum, Gray, in Wood, Index Test. Supp. f. 4. Catlow, Conch. 

 Nomenc. p. 4. Hanley, Desc. Cat. p. 7. 

 " ovata, (Gray,) Sowerby, Monog. Pholas, Thes. Conch, ii. p. 493, t. 

 107, f. 71, 72. Jay, Cat. 4th ed. p. 10. 



Martesia ovum, Gray, Ann. and Mag. viii. p. 383. H. and A. Adams, 

 Genera, ii. p. 331. Fischer, Journ. Conch. 2d ser. iii. p. 52. 

 Hab. West Indies. Hanley. 

 Much larger than either of the other species of this section of the genus. 



*** Valves with a single subcentral impressed rib; the anterior dorsal reflection 

 erect, separated from the outer surface of the valve. Gray, Ann. and Mag. 

 Nat. Hist. 2d ser. viii. p. 384. 



M. a pert a, Sowerby. (Sp.) 



Pholas a pert a, Sowerby, Zool. Proc. 1849. Sowerby, Monog. Pholas, Thes. 

 Conch, ii. p. 491, t. 108, f. 99, 100. 



Martesia aperta, Gray, Ann. and Mag. 2d ser. viii. p. 384. H. and A. 

 Adams, Genera, ii. p. 331. Fischer, Journ. Conch. 2d ser. iii. p. 52. 



Hab. Straits of Sunda. 



The character of the striae is different in this species from M. cuneiformis, 

 the undulations being finer and more angular. The shell is a young one, the 

 ventral plate being absent. 



M. Australis, Gray. 



Martesia Australis, Gray, Ann. and Mag. Nat. Hist. 2d ser. viii. p. 384. 

 H. and A. Adams, Genera, ii. p. 331. Fischer, Journ. Conch. 2d ser. 

 iii. p. 52. 

 Hab.'N. W. Australia. 



This species has not yet been figured, but Dr. Gray states that the anterior 

 waved concentric edges are rather distant, fewer than in M. striata. 



M. cuneiformis, Say. (Sp.) 



Pholas cuneiformis, Say, Journ. Acad. Nat. Sci. ii. p. 322. DeKay, 

 Moll. New York, p. 248. Kurtz, Cat. p. 3. Sowerby, Monog. Pholas, 

 Thes. Conch, ii. p. 495, 1. 104, f. 38, 39, 1. 108, f. 86, 87. Wheatley, 

 Cat. 



Pholadidea cuneiformis, Stimpson's Check List. 



Martesia cuneiformis, Fischer, Journ. Conch. 2d ser. iii. p. 52. H. and 

 A. Adams, Genera, ii. p. 331. Gray, Ann. and Mag. Nat. Hist. 2d 

 ser. viii. p. 384. 

 Pholas Edwardsii, Gray, Syn. Brit. Mus. 1820. 



" rudis, " " " " " 



Hab. Southern United States. West Indies. 

 Coll. Acad. Nat. Sci. Coll. Isaac Lea, LL. D. Coll. G. W. Tryon, Jr. 



M. rivicola, Sowerby. (Sp.) 



Pholas rivicola, Sowerby, Zool. Proc. 1849. Sowerby, Monog. Pholas. 

 Thes. Conch, ii. p. 496, t. 108, f. 90, 91. Adams and Reeve, Moll. 

 Voy. Samarang. p. 84, t. 23, f. 5. 



Martesia rivicola, Gray, Ann. and Mag. Nat. Hist. 2d ser. viii. p. 384. 

 H. and A. Adams, Genera, ii. p. 331. Fischer, Journ. Conch. 2d ser. 

 iii. p. 52. 

 Hab. Pantai River. 



This very distinct species is found burrowing in floating piles, on the Pantai 

 River, twelve miles from its mouth, where the water is perfectly fresh. 



1862.] 



