234 Bulletin 29 398 



created for the species the genus Bothrocorbula, considered by 

 Guppy and by Dall as only of sectional or subgeneric value 

 since a connecting series leads without break to Cuneocorbala . 

 Some aged individuals in our collection have become greatly 

 thickened and inflated so as to appear pathologic. Length 16, 

 altitude 10.5, semidiameter 4 ; a greatly thickened valve meas- 

 ures 16 X 11 X 9 mm. 



First described from Jamaica, this species is also reported 

 from Vamos-Vamos Station, Panama. 



Localities.- — (Exp'd'16) Bluff 3, Cercado de Mao ; Zone G, 

 Rio Gurabo at Los Quemados ; Zone I, Rio Cana at Caimito. 

 (Rather common). 



Genus Martesia Leach 

 Martesia Sancti-Dominici, n. sp. 

 Plate 39, Figure 22 



Shell small, ovate, with accessory dorsal and ventral valves ; 

 lateral valves with a nearly central, oblique deep groove, anterior 

 to which the valve is sculptured with exceedingly close, fine, 

 sharp and smooth, concentric threads, not crenulate, there being 

 no trace of radials ; posterior to the groove the concentric sculp- 

 ture is lacking and the surface smooth except for fine, irregular 

 growth striae. Length of shell 11, altitude 7, diameter 7.25 mm. 



The only species described heretofore from the Antillean Oli- 

 gocene is M. sphcBroidalis Guppy, and Dall thinks that should 

 probably be referred to another group. This species and the one 

 described below are apparently true Martesias, Gabb mentions 

 finding a small Martesia, but imperfect and showing no trace of 

 the accessory valve. 



Locality. — (Exp'd '16) Zone H, Rio Cana at Caimito. 

 (Rare). 



Martesia Sancti-Paidi, n. sp. 



Plate 39, Figure 23 



Shell showing clearly dorsal and ventral accessory plates ; 

 small, oblong, with an external oblique groove forming an internal 



