Jan., 1916. Annual Report of the Director. 27 



installed in a case with other salts in Hall 31. The fossil Carboni- 

 ferous tree from Michigan obtained from the St. Louis Exposition 

 was installed in Hall 33 in connection with other fossils from this 

 period. The series of Carboniferous crinoids and batrachians acqmred 

 during the year was similarly installed. The work of mounting 

 the invertebrate fossils upon tablets suitable for installation in floor 

 cases was carried on during the year as opportunity permitted and about 

 300 specimens were so prepared. Practically all the Pleistocene in- 

 vertebrate fossils have now been mounted in this way and some other 

 series have been completed. The Pleistocene fossils prepared were in- 

 stalled temporarily in a case in Hall 33. Specimens chiefly of Pleisto- 

 cene and Tertiary invertebrates which had been on exhibition were 

 removed from two wall cases and the cases placed in position in 

 Hall 35 to receive the skeleton of the sabre-tooth tiger and other 

 important specimens of the large collection of vertebrate fossils from 

 California presented by Messrs. Ayer, Butler, Linn and Ryerson. By 

 use of these two cases it was possible to place a representative series 

 of these fossils on exhibition. The specimens installed include a com- 

 plete mounted skeleton of the sabre-tooth tiger, several skulls of the 

 same species, several skulls and a large number of bones of the fossil wolf, 

 skidls and limb bones of the grotmd sloth, limb bones of the mastodon 

 and horse, skulls and other bones of the bison, and skulls and other bones 

 of various vulture-like and other birds. In order to make room for the 

 additional cases and secure a better grouping of the specimens, some re- 

 adjustment of the large cases in the Hall was also made. The speci- 

 mens of fossil elk skull and horns from Palos Park, Illinois, presented 

 by Mr. H. H. Honink, were also installed in this Hall. In Hall 59 a 

 disarticulated skeleton of the sabre-tooth tiger was installed in a table- 

 case, with each bone labeled so that the anatomical features of the 

 skeleton may be readily studied. In the laboratory of vertebrate 

 palaeontology a model of the jaws of the great Eocene shark Car- 

 charodon was completed, pains being taken to have the anatomical 

 details as nearly correct as possible. The jaws, as completed, have 

 a width of over six feet and an opening of four feet. For the 

 first row of teeth actual fossil specimens were used and for the suc- 

 ceeding rows casts of these. The modehng of the lines of the jaw 

 was based on careful studies of modem sharks. By carefiil atten- 

 tion to all these details it is believed that the characters of the 

 ancient shark jaw are reproduced with great fidelity in this model. 

 Owing to lack of space the model has not been placed on exhibition but 

 will be available for the new building. The mounting of the skeleton 

 of the sabre-tooth tiger received from California was modified so as to 



