254 0. C. Marsh—The Wings of Pterodactyles. 
marked facets for the sternal ribs. This peculiar method of 
strengthening the scapular arch has not been observed in any 
other vertebrates. 
THe Wine Bones. 
The three principal bones of the arm (humerus, radius, and 
ulna), present such similar characters in all Pterodactyles, that 
they need not be considered here in detail. It is important, how- 
ever, to bear in mind that the ulna, although but little larger 
than the radius, contributes the greater share of direct support to 
the enormously developed wing finger, which is on the outer 
or ulnar side of the hand. As this position has been a question 
of discussion among anatomists, it may be well to state, that 
the writer bases his opinion upon this point on the results of 
an examination of the best preserved specimens in Kuropean 
museums, as well as nearly all known in this country. The 
latter specimens settle the question beyond doubt. 
e views expressed by anatomists in regard to the bones of 
the wrist and hand of Pterodactyles are almost as various as 
the specimens investigated. Some of the restorations of these 
little to clear away the serious difficulties in the case. The 
main facts in regard to the carpus now known may be briefly 
stated as follows: 
In all Pterodactyles, there are two principal carpal bones, 
placed one above the other. These sometimes show indica- 
tions of being composite, but their constituent parts have not 
been satisfactorily determined. On the inner side of the wrist, 
articulating with the distal carpal, there is a smaller bone 
which has been called the “lateral carpal.” In addition to 
these three bones, some American Pterodactyles have on the 
inner side three ossicles, which may be sesamoid bones. ‘T'wo 
of these have been seen in a few Jurassic forms in Europe. 
Beside these, there is often found on the radial side of the 
wrist, and sometimes attached to it, a long, slender styloid 
