Page:Parasaurolophus walkeri, a new genus and species of trachodont dinosaur.pdf/10

6 these ﬁgures it is apparent that the left side of the head has been sheared downwards. The drawing (Plate IV) indicates the head as it would probably appear in true lateral aspect. Some allowance must be made for the difficulty involved in this reproduction; in fact, I am now of the opinion that the supraorbital region has not been sufﬁciently foreshortened vertically. The general size of the animal is indicated by the following measurements:

A comparison of numerous measurements indicates an animal somewhat smaller than Saurolophus osborni, for which Brown has estimated a total length of 32 feet.

The resemblance to Saurolophus is very apparent in the head in which the crest assumes an elongated spike-like character rather than the plate-like appearance of such forms as Corythosaurus and Stephanosaurus. The structure of the premaxilla and of the external nares, however, suggests aﬃnities with Corythosaurus and the lachrymal bone seems to be unique in its relationships. The size of the head, also, disregarding the crest, is very much less than in Saurolophus.

The body seems to be very like that of Saurolophus—massive and low-set. The pelvic girdle with the decurved anterior process of the ilium and the greatly expanded pre-pubis is strikingly similar to that of Saurolophus. The fore limb shows more differences in proportion: the humerus is almost exactly one-half the length of the femur, while in Saurolophus the proportion is considerably greater. In that genus, moreover, the radius and humerus are about equal in length, while in Parasaurolophus the radius is considerably shorter than the humerus.