636 Systematic Paleontology — Upper Devonian 



LlOPTERIA AUiaCULATA n. Sp. 



Plate LXIII, Fig. 1 



Description. — Shell small, very convex, body ovate, quite oblique; 

 height two-thirds length. ]\Iargin curving regularly from below middle 

 of anterior side to about middle of posterior side. Hinge-line long, 

 straight, ear large for this genus, limited by a broad sulcus near margin. 

 Cardinal margin of ear straight, continuous with, hinge-line. Wing 

 triangular, bounded by a broad sulcus, its margin concave, posterior angle 

 acute, produced. Surface marked by fine concentric striae. 



Length 20 mm.; height 11 mm. 



A single left valve only has been observed. This specimen is char- 

 acterized by its large ear, the cardinal edge of which is in same line with 

 hinge-line. It resembles L. gahhi in this respect but its body is much 

 more oblique. The reference of this species to the genus Liopteria is not 

 assured, the ear being so large as to place it near the genus Leptodesma,. 



Occurrence. — Jennings Formation, Woodmont Member, Ithaca 

 Fauna. Millstone 795. 



Collection. — ^Maryland Geological Survey. 



Genus LEPTODESMA Hall 



Leptodesma rogersi Hall 

 Plate LXIII, Fig. 3 



Leptodesma rogersi Hall, 1884, Pal. of N. Y., vol. v, pt. i, p. 176, pi. xxi, 



figs. 1-9. 

 Leptodesma rogersi Grabau and Shimer, 1909, N. Amer. Index Foss., vol. i, 



p. 426, fig. 556. 



Description. — Shell usually of small size, body ovate, very oblique, 

 length greater than height; anterior and basal margins broadly rounded, 

 posterior margin extended and abruptly recurved. Valves subequally 

 convex above. Eight valve somewhat depressed below, comparatively 

 higher than the left. Hinge-line longer than the length of the shell. 

 Surface M^ith fine concentric stria?. 



Length 25 mm.; height 15 mm. 



