NATURE 
[ April 6, 1882 
arch and wings of Pterodactyles involves many interesting 
points, some of which have been discussed by anatomists 
from Cuvier to those of the present day, but with little 
agreement of opinion. The cause of this diversity of 
Opinion is mainly due to the fact that the specimens exa- 
mined have been either too small or too imperfect for 
accurate determination of their more obscure parts. For- 
tunately, the museum of Yale College has among its 
specimens of Cretaceous Pterodactyles (some 600 in all), 
quite a number with the scapular arch and wing-bones 
nearly perfect, and in position. These specimens were 
nearly all of gigantic size, having in life a spread of wings 
from fifteen to twenty feet. They were also destitute of 
teeth, and belong to the order Preranodontia. Probably 
Fic. 2.—Caudal extremity of RAamphorhynchus phyliw us, Marsh; natural size. 
their great size induced special modifications of the sca- 
pular arch, which is here far more complicated than in 
any other members of the group. 
In the Jurassic Pterodactyles, the scapula is usually 
bird-like in general form and proportions, the upper or 
distal extremity being free and compressed. This is the 
case in the specimen here described. The scapula and 
coracoid may be co-ossified, as in the present fossil, or 
remain more or less separate. No clavicles have yet 
been found. The sternum here shows no distinct facets | 
for sternal ribs. 
In the Cretaceous genus, Pfevranodon, and probably also 
in some of the other gigantic forms from deposits of this 
age, the scapula and caracoid were not only solidly united, 
but the pectoral arch was further strengthened (1) by the 
ankylosis of several vertebrae, and (2) by the robust 
scapulz articulating on opposite sides of the common 
neural spine of these vertebra. This is virtually a repe- 
tition of the pelvic arch, on a much larger scale. The 
sternum also is massive, and shows well-marked facets 
for the sternal ribs. This peculiar method of strengthen- 
ing the scapular arch has not been observed in any other 
vertebrates. 
The Wing Bones.—The three principal bones of the 
arm (humerus, radius, and ulna), present such similar 
characters in all Pterodactyles, that they need not be con- 
sidered here in detail. It is important, however, 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 
Seen from the left side. 
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 European museums, as well as 
nearly all known in this country. The latter specimens 
settle the question beyond doubt. 
The 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 parts that have been published from 
time to time, and repeated in text-books, have done much 
to propagate errors, and 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 indications 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 “ late- 
ral carpal.” In addition to these three bones, some 
American Pterodactyles have on the inner side three 
ossicles, which may be sessamoid bones. Two of these 
have been seen in a few Jurassic forms in Europe. Be- 
sides these, there is often found on the radial side of the 
wrist, and sometimes attached to it, a long, slender sty- 
loid bone, having a rounded articular head on its carpal 
extremity. This is the so-called “pteroid bone,” to 
which allusion has already been made above. This bone 
Fic. 3.—Restoration of R/hamphorhynchus phyllurus, Marsh; one seventh natural size. 
and the “lateral carpal” which supports it, are usually 
placed by anatomists on the outer or ulnar side, but 
the first digit, or thumb, which is often considered 
wanting in Pterodactyles. According to this view, the 
American specimens prove conclusively that they belong | “lateral carpal’? would probably be the metcarpal of the 
on the radial side. 
The nature of the so-called pteroid bone has been much 
discussed, but without a satisfactory conclusion. 
careful study of many specimens, the writer is disposed 
After a | 
same digit. 
said— 
(1) That the position and structure of this appendage 
of the carpus correspond closely with that of the first digit 
In favour of this interpretation it may be 
toregard it, not as an ossified tendon, but as a part of | in some other reptiles, for example, Zewanodon. 
