Othniel Charles Marsh. ue 
His work on the Reptilia is not equally divided among the 
various orders, for the Dinosauria claimed his attention above 
all others. To this group he lent his best efforts, and he com- 
passed it so thoroughly as to be its sole master. It seems only 
necessary in this place to notice the complete restorations he 
made of some of these remarkable animals. In this list are 
included Anchisaurus, Brontosaurus, Laosaurus, Cerato- 
saurus, Camptosaurus, Stegosaurus, Triceratops, and Clao- 
saurus. It must be remembered that nearly all these animals 
were of gigantic stature, some of them the largest land 
animals yet known, and also that each restoration represents a 
number of separate investigations on the structure of the skull, 
the limbs, the vertebre, the pelvis, etc. In most cases, only by 
this means was it possible to bring together gradually, part by 
part, until the sum of the knowledge warranted a complete 
representation of the skeleton. The material of many of the 
genera he described is still in these various stages of progress, 
awaiting new additions of portions yet unknown in order to 
form a finished conception of the entire animal. His exten- 
sive report on the Dinosaurs of North America, published in 
1896, gave a synopsis of what he had accomplished up to that 
time, but as remarked elsewhere their philosophical treatment 
he had reserved for his final monographs. 
Probably, among the Reptilia, next in importance to his 
work on the Dinosauria is that on the Mosasaurs. In this he 
first announced the discovery of the dermal armor, the position 
of the quadrate, the finding of the stapes, the columella, the 
hyoid, the sclerotic plates, the quadrato-parietal arch, the malar 
arch, the transverse bone, the pterygoids, the pterotic bone, 
the sternum, the anterior limbs, the posterior limbs, the length 
of the neck, and details of the pelvic region. Thus he con- 
tributed a knowledge of some of the most essential characters 
of the skeleton in this group. In other groups of aquatic rep- 
tiles, he also brought out new genera and types of structure. 
Prominent among these may be mentioned Laptanodon, a 
toothless Ichthyosaurian. Marsh was the first to describe the 
remains of fossil serpents in the western Tertiary deposits, and 
likewise the first to discover the remains of flying reptiles in 
America. The latter were of unusually large size and remark- 
able for the absence of teeth. 
