Extinct Mammals 95 



onally across from the elevator. This specimen was pur- 

 chased from the finder, Handel T. Martin, and comes from the 

 Cretaceous chalk formation of western Kansas, like the ad- 

 joining skeletons on the wall, the great marine lizard 

 Tylosanrus below it, and the great fish Portheus above it. 

 The missing parts are painted in on the chalky background, 

 and the supposed outlines of the wing membranes are restored 

 in a very light tint. This skeleton is believed to be the first 

 original skeleton of Pteranodon to be placed on exhibition in 

 an American museum ; but there has been one (also found by 

 Mr. Martin) in the British Museum for some years past. 



The collections from the Pleistocene of Cuba obtained by 

 Mr. Brown's expedition in 1918 have been fully prepared for 

 study; also those obtained by Mr. Thomson in the same year 

 at the Snake Creek fossil locality in western Nebraska. 



Considerable preparation work was done upon Eocene and 

 Paleocene mammals during the year, chiefly upon small and 

 delicate specimens of much scientific importance 

 Extinct b ut £ no g rea t exhibition value. Various speci- 



mens of fossil crocodiles, of oreodonts and of 

 proboscideans were cleaned and prepared, mostly for study 

 purposes. A much crushed skull of Elephas columbi was pre- 

 pared and placed on exhibition, and a number of casts of 

 Siwalik proboscideans were mounted on panels in the exhibi- 

 tion cases. The mounting of a skeleton of the primitive mas- 

 todon Trilophodon is under way. Other additions are com- 

 pleted or in progress to the series of extinct elephants and 

 mastodons, which is one of the finest features of the Museum's 

 exhibits of fossil vertebrates. 



The restoration of the crushed skeleton of the giant bird 

 Diatryma has been undertaken in order to make an articulated 

 mount of the specimen. The most difficult and puzzling part 

 of it, the skull, has been satisfactorily reconstructed ; no very 

 serious difficulties are expected in the rebuilding of the 

 remainder of the skeleton. 



