GIRTY, NEW CARBONIFEROUS FOSSILS 237 



Glyptopleura inopinata sp. nov. 



Shell rather small, transverse, subquadrate. Width about 1.75 mm., which 

 is distinctly less than twice the height. Hinge line nearly as long as the 

 greatest width. Lower margin gently convex over the median portion, more 

 strongly curved in front and behind, convergent anteriorly with the dorsal 

 border. Posterior outline distinctly truncate and oblique, so that the post- 

 cardinal angle is distinct and obtuse. The anterior extremity is acutely 

 rounded above. The convexity is moderately high and obscurely constricted 

 across the middle, with the anterior portion more inflated than the posterior. 

 A small, deep, circular pit forms a depression a little above and a little pos- 

 terior to the center. The sculpture consists of large curved, inosculating ridges 

 which cross the surface transversely and more or less obliquely. There is a 

 smooth, finely striated border which surrounds the shell everywhere, save 

 along the hinge. 



The two valves are distinctly unequal, the left being the larger. The left 

 valve thus overlaps the other on all sides save along the hinge, at the ends 

 of which this arrangement appears to produce a primitive sort of articulation. 



Glyptopleura angulata sp. nov. 



Shell small, transverse, subovate. Hinge line straight, nearly as long as 

 the entire width, converging anteriorly with the gently convex lower border. 

 Anterior end strongly rounded. Posterior end more broadly rounded, not 

 much produced beyond the hinge extremity. Convexity high, chiefly centered 

 along a diagonal ridge, extending obliquely from near the upper anterior 

 angle to the lower posterior angle. As the lower margin also is oblique, the 

 descent to this margin is abrupt and regular, while that to the post-cardinat 

 angle is long and gradual. Anterior extremity of the ridge very prominent 

 and embellished with a little knob. 



Median pit situated above the middle (above the ridge) and near the mid- 

 dle transversely or a trifle posterior to it. 



Surface marked by a few rather coarse, strong, angular lirfe, more or less 

 transverse and inosculating. 



I 



Bairdia attenuata sp. nov. 



Shell rather large, very transverse. Lower margin nearly straight across 

 the median portion, strongly and equally turned upward at the ends, which 

 are pointed and slightly lower than the middle. Upper margin strongly con- 

 vex across the median portion, slightly concave near the ends. The point of 

 greatest convexity, and therefore of greatest height, is distinctly posterior and 

 the outline is more concave near the posterior than the anterior end. Convex- 

 ity moderate, compressed at the ends. Surface smooth. Left valve slightly 

 overlapping the right at the hinge ; elsewhere neither valve seems to extend 

 beyond the other. 



Bairdia cestriensis var. granulosa var. nov. 



This form is very closely related to B. cestriensis, of which Ulricli 

 figures two specimens, a large and a small. It is a more slender shell 



