so. THE STRUCTURE AND LIFE OF BIRDS cuHap. 
(1) The head of a pterodactyl is put on at right 
angles to its neck like a bird’s. The head in most 
reptiles continues the line of the neck. 
(2) The sternum or breastbone is broad and has 
a crest in the middle. This is just what might be 
expected where great strength is required in the 
fore limbs and the parts connected. The mole also 
shows a great development of breastbone: for bur- 
rowing this is as necessary as it is for flight. 
(3) The scapula is thin and blade-like, and the 
angle it makes with the coracoid is less than a right 
angle. 
(4) The ilium, the bone of the pelvis that unites 
with the backbone, is produced both ways, in front 
of and behind the thigh-joint. This is eminently 
characteristic of birds. 
Altogether the pterodactyl is so near to being a 
bird that we must, before leaving the subject, briefly 
show why he is after all a reptile. (1) The hand has 
at least four fingers, all but the last of these bear- 
ing claws; (2) there are no feathers ; (3) the ischium 
and pubis are at right angles.to the ilium, instead of 
running parallel as in birds ; (4) the pelvis is weak, 
so that it is extremely unlikely that he could walk 
upright. In spite of their presumable intelligence and 
high temperature, in spite of their power of flight, 
pterodactyls were still reptiles. Many species of them, 
some not larger than sparrows, others with a span 
of twenty-five feet from wing tip to wing tip, lived and 
throve when reptiles were the dominant class upon 
the earth, and, no doubt, they preyed upon lizards, 
birds, and mammals. 
