363 Dominican Fossils — Maury 199 



Venericardia cerrogordensis, n. sp. 

 Plate 33, Figure 3 



Shell sub-orbicular, somewhat compressed, posterior margin 

 truncate; beaks very low; ornamentation of seventeen low ribs 

 their crest strongly nodose, giving the effect of a series of minute 

 fish vertebrae; interspaces much wider than the ribs, those on the 

 anterior and central portions of the valve with two weak, second- 

 ary riblets or lateral keels of the main ribs, those on the posterior 

 region with a single radial thread ; all the interspaces but espec- 

 ially the posterior ones, strongly marked by wavy growth-lines; 

 substance of shell so thin that the interior is fluted by the exter- 

 nal sculpture; hinge weak; beaks rising very slightly above the 

 hinge. Length 20, altitude 19, semidiameter 6 mm. 



Distinguished by its compressed form, low beaks, low, 

 strongly nodose ribs. 



Locality. — (Exp'd '16) Cerro Gordo to Mao road, Rio 

 Cana. 



Genus Chama (Linne) Bruguiere 

 Chama involuta Guppy 



Plate 33, Figures 4, 5, 6 

 Chama involuta Guppy, Geol. Mag. London, dec. 2, vol. 1, p. 436, pi. 

 17, figs. 5a-c, 1874; Quart. Jour. Geol. Soc. London, vol. 32, p. 531, 

 1876. 

 Chama involuta Dall, Trans. Wagner Inst. Sci., vol. 3, pt. 6, pp. 



1398, 1586, 1903. 

 The left valve is attached, convex, beak spirally twisted, 

 surface more or less granose, ornamented with foliaceous scales 

 sometimes forming rows of radial spines; right, free valve, adorned 

 with fluted, concentric lamellae. The type is from Bowden. 



Locality. — (Exp'd' 16) Rio Cana, Guayubin to Mao road 

 (common); Cerro Gordo to Mao road. 



Chama caimitica, n. sp. 

 Plate 33, Figure 7 

 Shell oblong-ovate, attached by the left valve which is orna- 

 mented with conspicuous, irregular, vaulted scales, margin of 



