Page:Parasaurolophus walkeri, a new genus and species of trachodont dinosaur.pdf/31

Rh than in Trachodon and Claosaurus. The ulna is very much shorter than in Saurolophus, and only in Trachodon mirabilis is a shorter one recorded. The same relationship holds for the radius. The radius is shorter than the humerus, while in Saurolophus it is slightly longer (vide preliminary description, p. 6).

If Saurolophus osborni be regarded as the nearest relative of the present species, a most striking difference is shown by the manus. Saurolaphus appears from Brown’s ﬁgures to have the longest manus of any trachodont; on the other hand, Parasaurolophus has the shortest.

Adding together the lengths of humerus, radius, and metacarpal III, we obtain the following ﬁgures for the lengths of the fore limbs exclusive of phalanges:

It will be observed that Saurolophus has the longest fore limb and that Parasaurolophus has the shortest with the exception of Trachodon mirabilis. These relationships would not be greatly changed even if allowance were made for difference in size of the animals. While the fore limb of Parasaurolophus is short, it is relatively stout and is supported by a scapula of extraordinary size. May it not be that this arrangement is a direct consequence of the supposed attachment of the crest to the vertebral column? Short fore limbs would seem to be a necessity in order to permit the animal to lower its head while eating.

The pelvic girdle is distinctly of the type described by Brown for Saurolophus. It is deep and massive with decurved anterior process on the ilium and with expanded