186 KANSAS ACADEMY OF SCIENCE. 
Aviculopinna, and it is provisionally referred to that genus. It is liable to be 
confounded with no other species of either genus. It is much more liable to be 
mistaken for a coprolite. 
Aviculopinna knighti, n. sp. Plate XIV, fig. 2; plate XIII, fig. 6. 
Shell extremely large, slightly arcuate, compressed laterally, and having a 
very small angle of divergence at the end. Cardinal ridge small compared with 
the size of the shell. The striz meet the hinge at about a right or slightly 
oblique angle. They pass downward to about the middle of the shell, where they 
turn forward, as common among species of the genus. Both ventral and dorsal 
margins are similarly, though slightly arcuate. Length, 22 inches, with about a 
foot missing; height at widest place, 83 mm. 
Permian, Gage county, Nebraska. 
The beak of this fossil is missing, but the form and markings are such as to 
place it with all probability among the species of this genus. The young speci- 
mens of this species are remarkably long and narrow, presenting a peculiar ap- 
pearance. It is named in honor of Professor Knight, who collected the type. 
Aviculopinna nebrascenis, 0. sp. Plate XIV, figs. 1-1d. 
Shell moderately large, roughly triangular, compressed laterally, widening rap- 
idly toward the posterior. Hinge line straight; marginal ridge moderately promi- 
nent; ventral margin slightly arcuate; posterior extremity meeting the hinge at 
an obtuse angle, the lower third rounding forward to meet the ventral margin. 
Beak very indistinct and very near the anterior end of the shell. The surface is 
marked by strize passing slightly backward and downward two-thirds or three- 
fourths the distance across the shell, where they curve rather abruptly forward 
and downward, finally reaching the ventral margin as they fade out. The lines, 
as shown in the cast, are fairly approximate and not very prominent. They ap- 
pear to be nearly parallel to the ventral margin on the lower quarter of the 
shell. Length, 107 mm.; height a little in front of the posterior end, 41 mm. 
Permian, Gage county, Nebraska. 
This species differs from A. illinoiensis, which it most resembles, in being 
higher, in having a straight hinge, less distinct markings, and larger. It differs 
from A. pinneformis Geinitz, from the Permian of Europe, in not having any 
radiating striz. 
EXPLANATION OF PLATE XIII. 
Pinna? coprolitiformis. 
1. View of left side of specimen. 
1b. Diagrammatic reproduction of the strize from the middle to ventral margin 
of the opposite valve of another specimen. 
Allorisma sp. 
2 and 2h. The two valves of an Edmondia-shaped Allorisma. 
Aviculopecten nebrascensis. 
3. Flat valve, showing byssal notch. 
3b. Convex valve, cast, showing form and markings. 
3c. Outline of the same, showing convexity. 
3d. Larger specimen, with wavy strie and straight posterior side of shell. 
5 and 5b. Pedicle and posterior view of an undetermined brachiopod. 
Aviculopinna knighti. 
6. Left valve of specimen as it appears, one-fourth natural size. All other 
specimens natural size. 
