1911.] NATURAL SCIENCES OF PHILADELPHIA. 371 



Another Callocardia, undetermined, is recorded by Dall from Vamos- 

 a-Vamos (t. c, p. 1,261). 



Clementia dariena (Conrad). PI. XXVTII, fig. l. 



Meretrix dariena Conrad, Pacific R. R. Rep., V, p. 328, PI. 6, fig. 55. 

 Clementia dariena Conr., Gabh, Journ. A. N. 8. Phila. (2), VIII, p. 344, 



PI. 44, fig. 16. Dall, Trans. Wagner Inst., Ill, p. 1,235. 

 Toula, Jahrb., p. 725, PI. 27, figs. 9/10. 



A common clam in the Gatun Oligocene, also found in the presum- 

 ably later bed at Sapote, Costa Rica. No nearly related species has 

 been found in the Santo Domingo or Bowden beds. 



Cyclinella gatuneusis Dall. 



C. gatunensis Dall, Trans. Wagner Inst., Ill, p. 1,285, PI. 52, fig. 18. 

 In the best preserved specimens the sculpture of somewhat thread- 

 like concentric lines is about equally strong over the whole valve, 

 except near the beaks. Except for the tenuity of the shell, it might 

 be a Dosinia. 



MACTRID^J. 



*Mactra dariensis Dall. 



M. dariensis Dall, Trans. Wagner Inst., Ill, p. 895. 

 Vamos-a- Vamos . 



CORBTJLIDiE. 



Corbula gatunensis Toula. 



C. gatunensis Toula, Jahrb., p. 733, PI. 27, fig. 12. 

 This species attains a larger size than Toula's type, an example 

 measuring, length 26, alt. 22 mm. It is remarkable for the disparity 

 in sculpture between the ribbed neanic and the smooth mature 

 stage. 



Corbula sphenia Dall. 



Corbula (Cuneocorbula) sphenia Dall, Trans. Wagner Inst., p. 847, PI. 36, 

 fig. 10 (Chipola River Oligocene). 



A single valve agrees fairly well with the account of this species; 

 It has more and narrower concentric ribs than the figure of that species 

 shows, and is larger, length 22.2, alt. 13.5 mm. Probably identical 

 with C. dominicensis Gabb, but there are some slight differences. 



Corbula sericea Dall. 



Corbula (Cuneocorbula) sericea Dall, Trans. Wagner Inst., p. 848, PI. 6, 

 fig. 8 (Oligocene of Bowden, Jamaica). 



A single valve from Gatun is evidently referable to this species. 



♦Corbula alabamiensis Lea. 



C. alabamiensis Lea, Dall, Trans. Wagner Inst., Ill, p. 841. 



Described from the Alabama Eocene (Claibornian) ; reported by 

 Dall from the Gatun beds. 



