Notes on Mesozoic vertebrate fossils / by O.C. Marsh.

  • Othniel Charles Marsh
Date:
1892
Catalogue details

Licence: Public Domain Mark

Credit: Notes on Mesozoic vertebrate fossils / by O.C. Marsh. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    The tibia is shorter than the femur, and has a prominent cneinial crest. The distal end is much tiattened, and the astratralus is closely adapted to it. The fibula is very straight, withlts lower end' flattened and closely applied to the front of the tibia. The calcaneum is large, with its concave upper sur- face closely fitted to the end of the fibula. Of the second row of tarsals, only a single one appears to be ossified, and that is very small and thin, and placed between the calcaneum and the fourth metatarsal, nearly or (piite out of sight. The hind foot, or pes, had but three digits, the second, third, and fourth, all well developed and massive. The terminal ])halanges were covered with broad hoofs. The first and fifth digits were entirely wanting. A comparison of tlie limbs and feet of Claosfmrus, as here described and figui-ed, with those of three allied forms from tlie Jurassic, iStegosaurus, Laosmirus^ and CannHosaurus^ as shown on Plates IV and V, is especially instructive. These three genera have already been quite fully described and figured by the writer, but new ])oints of interest have been made out by the recent investigation of more perfect material. The present figures will show more accurately some of the mutual relations of these early herbivorous Dinosaurs to each other, as well as to their successors in Cretaceous time. The gradual changes that can be traced from one to the othei' will be discussed in a later communication. PiilmoseincHS, Leidy, 1856. A new reptilian genus and sjiecies, Pahwscincus coskitus, was ]>roposed by Dr. Leidy in 1856 for a single tooth found by Dr. Haydeu in the Judith Basin. This tooth was jnore fully described and figured by Leidy in 1S59.=^- The si)ecimen showed well-marked characters, and many similar teeth have since been found, both in the Judith Basin and in various other localities of the Laramie. A smaller species, ap|)arently of the same genus, is not uncoujmon in the Ceratops l)eds of Wyoming, iind a character- istic tooth is shown on Plate III, figure 3. This may be taken as the type specimen, and the species it represents may be called Palwoscinctis latus. The crown of the tooth in'this species is broader and the apex more pointed than in tlie first species described, and this is clearly shown in couiparino- the present figures on Plate III with those given by Leidy. * * I'ruc Aoacl. Nat. Sci. Phila.lclphia, p. 72, 1856; and Trans Amer. Pliil. Soc, p. 14G, pi. IX, tigs. 4a-52. ISS'J.
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