3o8 Field Museum oe Natural History — Reports, Vol. IV. 



Early in the year the paleontological laboratory was moved from the 

 quarters temporarily occupied in the section of taxidermy to Halls 77 

 and 78 of the West Annex. Side windows were cut, work tables were 

 fitted, and a sink, benches, and racks were installed in these halls. Racks 

 for 350 trays were erected in part of Hall 78 and a sorting table pro- 

 vided. The semi-prepared and duplicate material was carefully arranged 

 in these trays, and its complete preservation and accessibility thus as- 

 sured. In these quarters the preparation of vertebrate and invertebrate 

 fossils has been actively carried on through the year and a notable 

 amount of material worked out. The most important single piece pre- 

 pared during the year was a slab showing twenty-six skeletons of the 

 fossil water deer, Leptomeryx evansi. This slab was collected in South 

 Dakota in 1905. It was known at the time to be a remarkable specimen, 

 but its great richness in individuals was only realized on its being worked 

 out. In preparing the slab for exhibition the upper surface of the stone 

 has been chiseled away with great care, leaving the skeletons exposed 

 in high relief upon a background of the natural matrix. Not a bone 

 has been disturbed from its original position in the rock. Of the twenty- 

 six individuals shown, nine are in articulated position. Some are in a 

 natural reclining position, while others have legs, vertebral columns or 

 skulls dislocated and some are entirely disarticulated. The slab presents 

 one of the most notable aggregations of fossil mammals to be found in 

 any museum, and exceeds all in the number of individuals shown 

 associated. The size of the slab is four by seven feet. Sufficient mate- 

 rial was secured in connection with this to enable an articulated skeleton 

 to be mounted for exhibition beside it. The specimen as a whole will 

 make known for the first time the complete structure of this animal, 

 portions of which have been known to science for sixty years. The 

 preparation of the slab has occupied a large part of the time during the 

 year of Preparator Abbott under the supervision of the Assistant Curator 

 of Paleontology. Mr. Abbott was the discoverer of the specimen in the 

 field. A large number of other valuable specimens of vertebrate fossils 

 collected by the Museum expeditions of 1905, 1906, and 1908 in the 

 Western States have been prepared for exhibition during the year or have 

 been freed from their matrix so as to be readily available for study or 

 exchange. The specimens so prepared, determined, and installed during 

 the year include 28 miscellaneous specimens of Oligocene titanotheres, 

 three skulls and one jaw of Miocene creodonts, four carapaces and plas- 

 trons of Miocene tortoises and one each of Oligocene tortoise and Eocene 

 turtle. Eight specimens of Miocene horses, 12 of Miocene creodonts, 11 

 of Miocene camels and one each of Miocene rhinoceros and camel, were 

 also prepared sufficiently for identification. The skeleton of Canis diurus 

 received from the University of California was freed from adhering and 



