TRANSACTIONS OF WAGNER 



TERTIARY FAUNA OF FLORIDA 



low rostral keels, the dorsal one close to the dorsal margin of the valve ; 

 sculpture of concentric ribs like the lap-streaking of a boat, the short slope 

 above on each rib, about twenty-five in all, feebler on the rather low umbones, 

 and unequally developed on different specimens ; cardinal tooth stout, re- 

 curved ; in the left valve a narrow lamella projects from the margin behind 

 the socket. Lon. 10, alt. 6 (left valve) or 7 (right valve), diam. about 5 mm. 



This species, though more delicate, recalls C. alabainiensis Lea, but is less 

 twisted and pointed behind. 



Corbula (Cuneocorbula) seminella n. s. 

 PLATE 36, FIGURK n. 



Chipolan Oligocene of the Chipola River, Florida, Ball and Burns; Alum 

 Bluff beds at Oak Grove, Santa Rosa County, Florida, Burns; Pliocene (?) of 

 Port Limon, Costa Rica, R. T. Hill. 



Shell small, inflated, compact, with low beaks a little anterior to the 

 middle line, the left valve slightly smaller and enfolded below by the basal 

 margin of the right valve, which has a flexuous edge; beaks nearly smooth, 

 the valves below them with somewhat irregular, concentric undulations, and 

 more or less faint radial striation ; anterior end rounded, posterior end pointed, 

 with a single strong rostral carina, below which the basal margin is a little 

 emarginate. Lon. 4.5, alt. 3, diam. 2 mm. 



This is a very compact, solid, seed-like little shell, recalling C. Aldrichi 

 Meyer on a smaller scale. 



Corbula (Cuneocorbula) sericea n. s. 



PLATE 36, FIGURE 8. 

 Corbula cubaniana Guppy, Gcol. Mag., Dec. ii., vol. I, p. 449, 1874; not of Orbigny, 



Moll. Cnbana, 1853. 

 f Corbiila Lavalleana Gabb, Journ. Acad. Nat. Sci. Phila., 2d Ser., viii., p. 371, 1881. 



Oligocene marl of Bowden, Jamaica; Pliocene (?) of Port Limon, Costa 

 Rica; Hill. 



Shell much like the preceding species in general form, but slightly larger 

 and with less emargination beneath the rostrum ; the sculpture, however, is 

 quite different, being of very numerous, equal, fine, sharp, close-set ribs, the 

 interspaces crossed by fine, close, sharp radial striation, which at once distin- 

 guishes it from any of the allied species. Both valves are similarly sculptured, 

 the sculpture becoming obsolete on the beaks. Lon. 4.5, alt. 3.5, diam. 2.3 

 mm. The largest valve measures 5.4 by 4 mm. 



