1921 NATURAL SCIENCES OF PHILADELPHIA. 421 



Cardium (Trachycardium) dominicense Gal)b. Plate XXV, figs. S, 9. 



Cardiinn doniiniccnse (labb, Trans. Amcr. Philos. Soc, xv, 1873, p. 250; Journ- 

 A. N. S. Phila. viii, p. 344. Pilsbry and Brown, Proc. A. N. S. Phila., 1911, 

 p. 367 (Gatun). 



The ribs, except on the posterior slope, are smooth and rounded, 

 separated by narrow grooves. On the anterior end the ribs show 

 small erect processes or the scars where they have been. There are 

 also quite small processes along the posterior sides of the rest of the 

 ribs, nearly all worn off. On the posterior area each rib is split, 

 alternate ones of the resulting riblets bearing erect, oblique pro- 

 cesses. The posterior end is deeply serrate, each primary rib pro- 

 jecting. There are about 54 primary ribs. 



The whole basal margin is broken away, so that the true length 

 does not show in the figure. The type measures: length 38, alt. 44 

 (estimated), diam. of one valve 15 mm. 



Several young shells are more rounded in outline, and the ribs are 

 very closely spinose towards the margins. The posterior ribs show 

 only a trace of splitting. (No. 2769 A. N. S. P.). 



Type no. 2764 A. N. S. P. 



Cardium Unguatigris Maury appears to resemble this species 

 rather closely. 



Cardium tintinnabularum Maury. 

 One imperfect valve. 



Cardium (Trigoniocardia) haitense Sowerby. 



Cardium haitense Sowerby, Q. J. Geol. Soc, vi, 1849, p. .52, pi. 10, fig.ll. 



C. (Fraguin) haitense Sby., Gabb, Trans. Amer. Philos. Soc, xv, p. 251. 

 Cardium (Laevicardium) serratum L. 



Cardiam {Laevicardium) serratum L., Dall, Trans. Wagn. Inst., iii, p. ] 112. 

 Not recorded by Gabb, who left the specimens without name. 

 They are rather small, alt. 23 mm., but characteristic. 



Cardium (Laevicardium) venustum Gabb. Plate XXV, figs. 2, 7. 



C. {Laevicardium) venustum Gabb, Trans. Amer. Philos. Soc, xv, 1873, p. 251 . 

 The shell is longer than high, transversely oval, with very convex, 

 but somewhat narrow and markedlj^ prosogyrate beaks, which 

 project far more above the hinge outhne than in C. serratum. The 

 anterior and posterior areas are smooth, the median portion finely 

 ribbed, the ribs low, flattened, much wider than the intervals, which 

 are closely and finely striated transversely. There are about 50 ribs. 

 The right anterior cardinal tooth is peg-hke, higher than the poste- 

 rior. Lateral teeth compressed, the posterior, especially, much 

 thinner than in C. serratum. 



