186 PROCEEDINGS OF THE ACADEMY OF [April, 



to the Bowden shell. Gabb's L. acuta is certainly a distinct species, 

 as we have ascertained by the examination of over a hundred examples 

 of each. 



It is related to L. dodona Dall, which differs in several details of 

 form and sculpture. 



Area (Scapharca) sobrina n. n. 



Area consobrina Sowerby, Q. Jour. Geol. Soc, VI, 1849, p. 52, PI. X, fig. 



12. Not A. consobrina Orbigny, 1843, or of Guppy. 

 A. (Anadara) consobrina Shy., Gabb, Trans. Amer. Philos. Soc, XV, p. 253. 



The shell is nearly equivalve, oblong, strongly inflated, tapering 

 posteriorly, the anterior end somewhat oblique. Beaks moderate, 

 mesially impressed, situated at about the anterior fourth of the 

 length. The cardinal area is rather narrow, marked by several 

 concentric grooves. The left valve is slightly larger, with sculpture 

 of 33 rather high ribs with abrupt sides. Except on the posterior 

 dorsal slope the ribs are closely sculptured with transverse granules, 

 which are continued as thin raised striae over the intervals. The 

 anterior and posterior ribs are divided by a groove along the summits. 

 The right valve is similar, but the granules on the ribs are almost 

 obsolete. The hinge has 29 teeth in front, 40 behind, the row being 

 continuous except for a small irregularity. Border very deeply 

 crenated. 



Length 50, alt. 30, diam. 29 mm. 



" 48, " 30, " of right valve, 14 mm. 



Cotypes No. 2737, A. N. S. P. 



Area actinophora Dall has more ribs, is narrower posteriorly, and 

 differs in proportions. A. sohrina is not very closely related to 

 A. halidonata Dall of the Jamaican (Bowden) Oligocene, which we 

 have not found in the Santo Domingan collection. It is very much 

 like A. dariensis Brn. & Pils., but the valves are more convex and 

 the details of rib sculpture differ. It also is a larger species. 



Area (Scapharca) copiosa n. sp. 



The shell is oblong, somewhat trapezoidal, strongly inflated. 

 Left valve slightly larger. Beaks impressed in the middle, in front 

 of the anterior fourth. Cardinal area moderately wide, marked with 

 about 4 grooves on the anterior, 5 or 6 on the posterior part. Sculp- 

 ture of 30 ribs, in the left valve about equal to the deep intervals; 

 at the anterior end the ribs have flat, or somewhat concave summits. 

 Both ribs and interstices are crossed by fine, close concentric threads, 

 which give place to mere growth-lines on the posterior area, where 

 the ribs weaken. The right valve is like the left except that the 



