152 



PROCEEDINGS OF 7 HE NATIONAL MUSEUM. 



vol.. XXXII. 



The figure below represents the back of tlu' nkull with the atlas attached, and the 

 post-occipital bones in place. The axis and third cervical were also found in posi- 

 tion. These will serve to distinguish the present species from the others of the 

 genus, as they are proportionally much longer and of lighter structure. 



The hind feet of the present sj^ecimen agree in general structure w'ith those of 

 Morosatm-ns grandis, but differ in having the first digit unusually large and massive 

 in comparison with the others. Tlie third, fourth, and fifth are especially slender. 



The writer has been unable to find the "other parts of the skele- 

 ton" mentioned b}' Marsh in his original description. Moreover, a 

 rough field sketch accompanying- the t3'pe specimen only shows the 

 posterior portion of the skull, atlas, axis, and third cervical, and 

 these elements in all probability constitute the type specimen. 



The hind foot which is 

 mentioned as appertaining 

 to the ' ' present specimen " 

 is also missing, unless 

 Marsh refers here to the 

 right pes (Cat. No. 5369, 

 U.S.N.M., | 1655 | Marsh's 

 accession number, figured 

 in Plate XXXVII, fig. 2, 

 in Dinosaurs of North 

 America), and which he 

 has identified as belonging 

 to Morosaurus agilis. See 

 fig. 2J. Marsh must have 

 inadvertently referred the 

 pes to this species as the 

 original field labels still 

 with the specimens dis- 

 cussed here, show the type 

 was collected in 1883, while the hind foot was not found until 1888, five 

 years later. Fig. 1, Plate XXXVII, Dinosaurs of North America rep- 

 resents the right manus (Cat. No. 5371, U.S.N.M., Marsh's original 

 number }1655|) of M. agilis^ also in the collection of this Museum. See 

 fig. 2«. With the foot are the radius and ulna. Both of the feet 

 were collected by Mr. Felch at the same time and place, "(Tarden 

 Park," near Canon City, Colorado, from the Upper Jurassic (Morrison 

 Beds), in 1888. Whether the}^ belong to the same specimen or even 

 to the same species, in the state of our present knowledge can not be 

 determined with any degree of certainty. 



The "quarry" at Canon Cit}^, where Marsh secured the remains of 

 various specimens of the Dinosauria, is commonly known as a "gen- 

 eral quarry,'" as from it have been obtained the remains of a large 

 number of individuals representing several genera and species in a 



Fig. 1. — Skull of MoRosACRrs agili.s ((Iat. No. 6384), pos- 

 terior VIEW, i NAT. SIZE, a, PEOATLAS; h, LATERAL PLATE 

 OF ATLAS; C, ODONTOID PROCESS, OR CENTRUM, OF SAME; 



en, exoccipital; /, intercentrum of atlas; n, neural 

 CANAL; p, parietal; 'po, postorbital: .s, si^uamosal; so, 

 -supraoccipital. 



