XIV. A MOUNTED SKELETON OF DICERATHERIUM 

 COOKI PETERSON. 



By O. a. Peterson. 



{Science, Vol. XXIV, pp. 281-282, 1906; Ann. Car. Mu^., Vol. IV, 

 pp. 47-48, text-figures 12, 13, plate XIV, 1907 ) 



Some recent publications by Professors Frederic B. Loomis^ and 

 Erwin H. Barbour^ on Diceratherium remains from the now well- 

 known Agate Spring Fossil Quarries in Sioux County, Nebraska, 

 have appeared, but no detailed description of the osteology, outside 

 of an illustration of a half-relief mount by the latter author, has 

 hitherto been published. The present paper is only intended to briefly 

 treat of the articulated skeleton recently placed on exhibition in the 

 Hall of Mammalian Paleontology of the Carnegie Museum, reserving 

 for a later publication more detailed work on the extensive collection 

 of material representing this genus in this museum. 



No. 2499, the basis of the articulated skeleton, consists of the skull 

 with the lower jaws, the complete cervical series, seven dorsals, a 

 number of ribs, portions of both fore limbs and fragments of hind 

 limbs and feet. This material establishes a good basis for the de- 

 termination of the different parts of the bony structure in this species 

 and the composite skeleton is thought to accurately represent D. cooki. 



From the large number of individuals already cleared from the 

 matrix we are still unable to state definitely whether there were 

 eighteen or nineteen dorsals in the presacral series. On the other 

 hand the number of the lumbars as well as the cervicals and sacrals 

 are well established from our material, while the caudal series is 

 approximately correct. 



Skull. 



The skull used in this restoration (No. 2499) is typical of Dicera- 

 therium cooki described in previous publications. The teeth are 

 somewhat more worn down than those of the type No. 1572, showing 

 that the crotchet on M- is completely united with the already broad- 



^Amer. Jour. Sci., Vol. XXVI, pp. 51-64, 1908. 

 'Nebraska Geological Survey, Vol. Ill, Plate i, 1909. 



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