383 Dominican Fossils — Maury 2:9 



Santo Domingo. That species however, has an intermediate rib 

 between every pair but of these secondary ribs a few only appear 

 on our shell. As occasionally a rib doubles in Woodwardi our 

 shell may be a mutation of that species with this tendency great- 

 ly increased. 



Locality. — (Exp'd '16) Bluffs 2 and 3, Cercado de Mao. 



Chione {Lirophora) Hendersoni Dall 

 Plate 37, Figure 8 

 Venus paphia Guppy, Quart. Jour. Geol. Soc. London, vol. 22, p. 292, 



1866. Not of Linne. 

 Chione paphia Gabb, Trans. Arner. Phil. Soc, vol. 15, p. 249, 1S73. 

 Venus paphia Guppy, Quart. Jour. Geol. Soc, vol. 32, p. 292, 1876. 

 Chione (Liophora) He?idersonii Dall, Trans. Wagner Inst. Sci., vol. 

 3, pt. 6, p. 1295, pi. 55, fig. 22, 1903. 



The Bowden shells are described as having about fifteen ribs, 

 sometimes so close together as to obscure the interspaces. Our 

 Dominican specimens show variation in the number of ribs and 

 they are not so crowded. The most closely sculptured shells 

 have about eleven large ribs and three to five small ones on the 

 beaks. Others have only six or eight large ribs. This difference 

 leads one to conclude that the ribbing is inconstant and that 

 probably our shells are the same species as the Jamaican. 



Localities — (Exp'd '16) Bluff 1, Cercado de Mao; Zone G, 

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



Genus Peteicola Damarck 



Petricola cairn itica, n. sp. 

 Plate 37, Figure 11 



Shell, rounded, convex, rather thin, gaping posteriorly ; 

 sculptured with occasional concentric ridges and characterized by 

 the surprising and varied radial sculpture. On the umbonal 

 region the radials anastomose forming series of very narrow, 

 elongated V-shaped designs, the apices extending downwards ; 

 after a distance of about seven millemeters from the beaks the 

 radials suddenly become coarser, more distant, more oblique and 

 irregular, on the face of one valve breaking up to form a series of 



