650 S. W. WILLISTON 
matrix of the right humerus. ‘The two bones hence give the characters 
of the complete humerus with the exception of the proximal outer 
part. The humerus resembles not a little that of Eryops, a figure 
of which, more reduced, I have given for comparison (Fig. 4), although 
a little more slender, as are, indeed, all the bones of the extremities. 
The two expanded extremities are twisted at an angle of about sixty 
degrees, the shaft between them abruptly and much constricted, about 
8 by ro™™ in diameter. The proximal anterior face is somewhat 
concave. ‘The distal portion has a large rounded radial convexity on 
its outer side, above which, separated by a groove at the outer side, 
is a small process, evidently quite like that of Eryops. The inner 
condyle is somewhat thickened; the entepicondylar margin is con- 
vex from above downward, but wholly without an epicondylar 
foramen, such as is present in the related genus Acheloma Cope. 
The two extremities of the right ulna were found free in the wash, 
distinguished from the reptilian ulna found with the specimen by 
their much smaller size and the less produced olecranon. I have 
figured them in the plate (Fig. 4), separated by the same relative 
distance as those of the ulna of Eryops. ‘The proximal portion is 
convex on the inner side, thinned above and below. ‘The outer side 
is concave for the radius, with the humeral articular surface, or sig- 
moid cavity, showing more from that side. The olecranon is rugose. 
The distal extremity is but slightly expanded, a little thickened in the 
middle at the end, gently convex on the dorsal, and concave on the 
palmar surface. 
The extremities of what I believe to be the radius are among the 
fragments recovered in the wash, but the present impossibility of 
distinguishing them from the reptilian remains renders their descrip- 
tion inadvisable. I have outlined the bone in the restoration from 
Eryops. 
A mass of matrix containing nine carpal bones united in their 
proper relations was secured. Their distinction from the reptilian 
specimen is assured by their smaller size, and the determination of the 
carpal bones in that specimen. Their relative size and position, as 
I determine them, will be seen in the restoration. It is evident that 
two of the proximal bones are missing, and they are shown in shaded 
outlines in the figure. 
