86 



O. O. Marsh — JVew Dinosaarian Reptiles. 



On the distal caudals, the lateral cavity has nearly or quite 

 disappeared. All the caudal vertebrae are proportionally shorter 

 than in Diplodocios* and their chevrons have no anterior 

 projection, as in that genus. 



Fig. 1. 



Fig. 2. 



Figure 1. — Caudal vertebra of Barosaurus lentus, Marsh; side view. 



Figure 2. — The same vertebra, in section; front view. 



a, anterior end; c, face for chevron; /, lateral cavity; p, posterior 

 end ; s, section. 



Both figures are one-eighth natural size. 



The remains on which the present description is based are 

 from the Atlantosaurus beds of Dakota, about two hundred 

 miles further north than this well-marked horizon has hitherto 

 been recognized. 



For important aid in securing the fossils above noticed, the 

 thanks of the writer are due to Mr. J. B. Hatcher, Dr. C. E. 

 Beecher, and Mr. f r. L. Cannon, Jr. The type specimens will 

 be more fully described and figured by the writer under the 

 auspices of the IT. S. Geological Survey. 



New Haveu, Conn., December 21, 1889. 



Explanation op Plate I. 



Figure I. — Left tibia of Orniihomimus velox, Marsh; a, front view; b, distal 

 end ; c, transverse section. 



Figure 2. — Left metatarsals of same specimen; a, front view ; b, proximal ends; 

 c, transverse section ; d, distal ends. 



Figure 3. — Phalanges of second digit of same foot ; front view. a. first pha- 

 lange ; b, second phalauge ; c, third, or terminal phalange. 



Figure 4. — Left metacarpals of same species, perhaps of smaller individual; 

 front view. 



Figure 5. — Left tibia of young Ostrich (Struthio camelus. Linn.) ; a, front 

 view ; b, distal end. The separate calcaueum was first observed by 

 the writer's assistant, Dr. G-. Baur, who prepared the specimen. 



Figure 6. — Left metatarsals of young turkey (Meleagris gallipavo, Linn.) ; A, 

 front view ; b, proximal ends. 



a, astragalus ; as, ascending process of astragalus ; c, calcaneum ; /, fibula ; /', 

 face for fibula ; it, second metatarsal ; in, third metatarsal ; iv, fourth metatarsal. 



Figures 1-4 are one-third natural size, and figures 5 and 6, one-half natural size. 



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