20 Department of Vertebrate Palceontology. 



was about fifteen feet long. According to Professor Cope's 

 views, by which Mr. Knight was chiefly guided in making this 

 and the following restoration, the animal was an active and 

 powerfiil leaper, and the model, representing two fighting 

 Lcelaps, carries out this conception. One-seventh natural 

 size. Length of base, i8 inches. 



Cope, Proc. Acad. Nat. Sci. Phila., 1866, p. 275; Proc. Amer. Philos. 



Soc, XXX, p. 240, May, 1892. 

 Marsh, Dinosaurs of North America, pp. 157-163, pi. xiv. 



Price, $20 (2 figures, complete). 



No. 4. Naosaurus claviger Cope. 



From the Permian Beds of Texas. This belongs to the prim- 

 itive Reptilian order Pelycosanria of Cope, but represents a 

 highly specialized side-branch, related to the Rhynchocephalia 

 or Proganosaiiria as shown by Baur and Case. The precise 

 object of the extraordinary rigid fin on the back is not known; 

 it was humorously suggested by Cope that it might have been 

 used as a sail. It was, perhaps, chiefly ornamental. Differ- 

 ent species of Naosaurs reach from three to ten feet in length, 

 and the dorsal fin reaches a length even greater than that 

 shown in the model. One-fifth natural size. Length of base, 

 12 inches. 



Cope, Proc. Amer. Phil. Soc, 1878, p. 510, and subsequent papers. 

 Baur & Case, Morphology of the Skull of the Pelycosauria, Anatom. 

 Anzeiger, Bd. XIII, p. 109, Jena, 1897. 



Price, $12. 



No. 5. Cervalces americanus {Harlan). 



This Pleistocene American Elk was of the size and propor- 

 tions of the living Moose, but had horns almost as large as 

 those of the Extinct Irish Deer of Europe, and expanded in 

 three planes of growth at right angles to each other. The 

 ihodel is based on a remarkably perfect skeleton found in New 

 Jersey and mounted in the Princeton University Museum. 



