Notice of New Dinosauria. 



333 



Morosaurus lentus, sp. nov. 



One of the most interesting specimens of Sauropoda in the 

 Yale Museum pertains to a species of Morosaurus much 

 smaller than M. grandis, the type, and differing materially in 

 other respects. The skull is not known, but nearly all the 

 important parts of the skeleton are well represented, and in 

 excellent preservation. The individual was not fully adult, 

 and hence, the elements of the vertebrae and sacrum are, in 

 most cases, separate, thus affording special facilities for inves- 

 tigation. 



The limb bones and feet show that the fore and hind legs 

 were much shorter than those of the other species of the 

 genus. The vertebrae, also, are shorter, more massive, and the 

 cavities in them, smaller. All parts of the skeleton preserved 

 are of similar density, indicating that the whole osseous struc- 

 ture of the animal was more solid than any other of the known 

 Sauropoda. The vertebrae of the cervical and dorsal regions 

 have their centra more depressed than in the other species of 

 this genus, and may easily be distinguished by this feature 

 alone. The neural arch rests directly upon the centrum, 

 instead of being elevated on pedestals above the articular faces. 

 This feature is well shown in the figure below. 



Fig 2. 



Figure 2. 



-Posterior cervical vertebra of Morosaurus lentus, Marsh ; front view. 

 One-fifth natural size. 



The type specimen of the species here described indicates an 

 animal about thirty feet in length. The known remains are 

 from the Atlantosaurus beds of the Upper Jurassic, in 

 Wyoming. 



