1911.] NATURAL SCIENCES OF PHILADELPHIA. 369" 



lunule has radial lamellae only, and is defined by a deep groove. The 

 lanceolate escutcheon is concave, with sculpture of smooth raised lines 

 continued from the concentric lamella?. The basal and anterior 

 valve-margins are crenulated inside, as is also the margin along the 

 lunule. 



Length 19.5, alt. 19, semidiameter 8 mm. 



This species resembles C. woodwardi Guppy, from the Bowden 

 Oligocene, but differs by having a smaller lunule, and in the details 

 of sculpture, as shown in the figure.. 



Chione sp. undet. 



A species resembling C. woodwardi, but reaching a length of over 

 40 mm., occurred as casts retaining very little of the shell. 



Chione (Lirophora) ulocyma (Dall). 



Trans. Wagner Inst., Ill, p. 1296, PL 42, fig. 5 (Miocene of Alum Bluff, 



Calhoun County, Fla., etc.). 

 Venus (Chione, Lirophora) ulocyma Dall, Toula, Jahrb., p. 724, PI. 25, 



figs. 20-22. 



There seem to be two forms : one agreeing with the' type figure of 

 ulocyma in having coarse concentric sculpture; the other having 

 much finer, more numerous wrinkles. In the former the beaks appear 

 to be smooth, but possibly as the result of wear. In the finely sculp- 

 tured form the beaks have about five thin concentric widely spaced 

 lamina?, preceding the corrugated stage, such as are described for 

 C. burnsi Dall. This race may be called C. ulocyma holocyma. In 

 this race, as well as in the coarse form, the radial grooves are very 

 strongly developed. 



*Chione (Liriphora) mactropsis (Conrad) 



Crateloupia mactropsis Conrad, Pacific R. R. Rep., V, p. 328, PI. 6, fig. 54. 

 Chione (Liriphora) mactropsis Conr., Dall. Trans. Wagner Inst., Ill, p. 

 1294. 



Eocene and Oligocene of Isthmus of Darien, Blake; Gatun and 

 Vamos-a-Vamos, Panama Canal, Agassiz. 10.5 K. w. of Colon, Hill 

 (Dall). Chiriqui, Dr. John Evans (Gabb). 



Pitar centangulata n. sp. 



Pitaria (Hyphantosoma) n. sp., Toula, Jahrb., p. 726, PL 28, fig. 16. 

 Cf. Pitaria (Hyphantosoma) opisthogrammata and fioridana Dall, Trans. 

 Wagner Inst., Ill, p. 1,267. 



This species is closely related, as Toula has pointed out, to the 

 above-named species of Dall. It differs from P. fioridana (from the 

 Chipola Oligocene) in the rotund-oval, not " subtrigonal " shape,- 

 and in the even rotundity of the valves, without trace of a flattening 

 or sulcus running to the posterior base; but it agrees with fioridana 



