SOME NEW DEVON IC FOSSILS 279 



In further detail, the ventral valve is subcircular or transverse 

 with strongly defined and thickened adductor and divaricator scars. 

 These are not however as large as in H. proximus. The 

 beak is convex and slightly elevated but the rest of the valve is 

 depressed or fiat with a tendency to turn up about the margin and 

 with indications of a broad and low median fold. The striae are 



Hipparionyx minor 



sharply elevated, increase very rapidly by implantation and on the 

 cardinal slopes curve forward, out and back, in very characteristic 

 manner. Very fine concentric lines are visible in the intervals 

 between the striae. The dorsal valve is highly convex ; the beak 

 is not prominent, the convexity is generally uniform with slightly 

 depressed cardinal slopes and sometimes a trace of a median groove. 

 On the interior is a strong bifid cardinal process and a short median 

 septum. 



Lower Devonic. Edmunds Hill, Chapman Plantation, Me. 



Orthothetes (Schuchertella) woolworthanus Hall 

 mut. gaspensis now 



See Strophomena woolworthana Hall. Pal. N. Y. 1859. 



3 : p. 192, pi. 17, fig. 1,2; and 

 Orthothetes woolworthanus Hall & Clarke. Pal. N. Y. 



1892. v. 8, pt 1, pi. 11, fig. 25-29, 31 



It is not easy to discriminate species differentials in members of 

 the genus Schuchertella (Orthothetes). In the forms before us 

 we are presented with a shell which approaches in general aspect 



