PROCEEDINGS 



OF THE 



ACADEMY OF NATURAL SCIENCES 



OF 



PHILADELPHIA 



1870. 



Jan. 4th, 1870. 

 The President, Dr. Ruschenberger, in the Chair. 

 Thirty members present. 



Prof. Leidy called the attention of the members to a curious fossil, which 

 had been sent to him for examination last fall by Prof. Hayden. It was found 

 in Colorado, and loaned to the latter by Dr. Gehrung, of Colorado City. 

 Prof. L. remarked that when first received, the specimen strongly recalled to 

 his mind the upper part of the face of the wonderful Sivatherium of the Sivalik 

 Hills of India. It, however, presents so many peculiarities, that among other 

 conjectures he thought it might have pertained to the pelvis of a chelonian, 

 but had finally concluded that his first suspicion was the correct one. The 

 specimen corresponds with that portion of the face of Sivatherium comprising 

 the upper part of the nose together with the forehead and anterior horn cores. 

 As is described to be the case in the corresponding portion of the skull of 

 Sivatherium, all the bones comprising the fossil are completely coossified so as 

 to leave no trace of the original position of the sutures. The nasal and con- 

 tiguous bones are of great thickness, and as solid as Ihose generally of the 

 Sirenians. The animal to which the fossil belonged was nearly as large as 

 the Sivatherium. 



The horn cores are nearly like those of the latter in form, size, and relative 

 position to each other. They are conical knobs, slightly trilateral, and with 

 an obtusely rounded summit, which is more porous than the bone is else- 

 where. They are moderately divergent, and their summits project more over 

 their base externally than in Sivatherium. The space between the cores ex- 

 tending across the forehead forms a continuous concavity ; and the surface 

 from the end of the nose to the broken border of the fossil posterior to the 

 cores forms a moderate convexity. In Sivatherium the corresponding surface 

 from the slope of the forehead to the convex rise of the nasals forms a deep 

 concavity. 



The face, as formed by the nasals and their apparent conjunction with the 

 maxillae in advance of the horn cores, is very short in comparison with that 

 of Sivatherium. The coossified nasals are proportionately shorter, broader. 



1870.] 



