208 
Kirtley F. Mather 
Internally, the anterior adductor muscle-scar is comparatively 
large and deep and is bounded behind by a sharp crescentic 
ridge; the surface of the internal cast is crossed by irregular 
undulations parallel to the margins of the valve. 
In the material at hand only a small portion of the external 
surface of the valve, adjacent to the cardinal margin, is pre- 
served. It is marked by close-set, concentric striations parallel 
to the posterior margin. 
Dimensions of type, a left valve, are : length, 8.0 mm. ; height, 
4.0 mm. ; convexity of valve, about 1.5 mm. ; length of hinges 
line, 4.5 mm. 
Remarks. It is plainly evident that this species is congeneric 
with the forms to which in 1885 HalF^ gave the name Sphenotm 
but unfortunately the validity of that genus is not quite clear. 
Hind^^ believes it to be a synonim of Sanguinolites and if his 
diagnosis of the latter is correct such would seem to be the case. 
Horizon and locality. Hale formation: East Mountain, Fay- 
etteville, Arkansas (Station 136). 
GRAMMYSIID^ 
Genus EDMONDIA De Koninck 
Edmondia subtruncata Meek 
Plate XV, figure 2. 
1872. Edmondia subtruncata. Meek, U. S. Geol. Surv. Nebr., p. 215, pi. 
2, fig. 7. 
Upper Coal Measures: Rock Bluff, Nebraska; Atchison, Kansas. 
Lower Coal Measures: Illinois. 
1894. Edmondia subtruncata. Keyes, Mo. Geol. Surv., vol. 5, p. 127. 
Upper Coal Measures: Kansas City, Missouri. 
1899. Edmondia subtruncata? Girty, U. S. Geol. Surv., 19th Ann. Rep., 
pt. 3, p. 580. 
Upper Coal Measures: Atoka Quadrangle, Indian Territory. 
1903. Edmondia subUmncata. Girty, U. S. Geol. Surv., Prof. Paper 16, 
p. 448. 
Upper portion of Hermosa formation: San Juan region, Colorado. 
Description. Shell longitudinally sub-ovate, outline of dorsal 
margin very slightly convex in the middle and curving more 
gently toward the anterior margin than toward the posterior, 
the latter margin curving abruptly into the cardinal margin; 
valves moderately convex, the greatest convexity being near the 
middle, surface of valves regularly curved, somewhat abruptly so 
