6 
DRAGONS OF THE PRIME. 
Jan,, 1892. 
more than the reptile, although, indeed, it is not actually 
united to the ilium as is the case in most birds, though not in 
Apteryx. In Apteryx, too, the pubis lies parallel to the 
ischium ; in the crocodile it projects forwards. In the 
Dinosaur, these two conditions are combined, for it has both 
a bone projecting in front like the pubis of the crocodile 
(Fig. 5 Or ,,pb.) and also a second bone—the post-pubis (pp.) 
projecting behind parallel to the ischium, like the pubis of 
birds. 
It was thought at one time that the pubis of birds corre¬ 
sponded to the backwardly projecting part of the pubis of 
Dinosaurs, and the pubis of reptiles to the forwardly 
projecting part. It seems certain, however, now, that such 
is not the case. The backward projecting pubis of birds 
really corresponds to the forward projecting part of the 
Dinosaur’s pubis. In the evolution of the birds, the pubis 
has become swung backwards from the forward to its present 
position, a movement which actually takes place in the 
development of the individual. The bone, however, in the 
Dinosaurs which looks like the pubis of birds is a secondary 
structure which has been developed in relation to the semi¬ 
upright position of the body, for the better balancing of the 
latter and for the attachment of muscles which keep the 
body from falling forward. 
All the semi-erect Dinosaurs have this bird-like arrange¬ 
ment of the bones of the pelvis; but some of the less 
specialised forms show their connection with the reptiles by 
possessing the typically reptilian number of five toes on the 
hind feet, and also in the fact that the animal walks on the 
soles of its feet like the crocodile and not on the toes 
as birds do. Ocher Dinosaurs, however, resemble birds 
not only in the structure of the pelvis, but also in that of the 
hind limbs; at the same time there are interesting differences 
between the two groups. 
(1).—The hind-limb (Fig. 6, B., D.), both in birds and in the 
most bird-like Dinosaurs, is divided into four regions, of which 
the uppermost (thighbone, or femur, Fm.) is similar in both. 
In the Dinosaurs the third region is much shorter than in the 
birds. 
(2.)—In birds the second of these regions is composed of 
two bones : one, the tibio-tarsus is strong and stout; the 
other, the fibula , is very thin, and does not reach to the lower 
end of the former. In the Dinosaurs the two bones are 
almost equally strong, and though of the two the fibula is the 
weaker, yet it is just as long as the tibio-tarsus. 
(3.)—In birds the third section of the limb, or metatarsus , 
