NATURAL SCIENCES OF PHILADELPHIA. 223 



the second and third are broader than long, the first and fourth 

 longer than broad, and with an angle on the outer anterior side 

 of the crown. Tiiere is an inflection or groove of the enamel on 

 both inner and outer sides of the crown, and one enamel area before 

 and one behind them on all excepting the last molar, where there 

 are two in front. First nearly twice as large as last molar. Lower 

 incisor with smooth enamel, and angulate on the extero-anterior 

 border. Karaus stout. Length of molar series m. .OK; ; length 

 of first molar m. .005 ; width of first molar m. .004 ; width of last 

 molar m. .0035; transverse diameter of incisor m. .004; depth of 

 ramus at m. 2.012. 



The regular diminution of the size of the teeth from front to 

 rear is characteristic of this species; according to Dr. Leidy their 

 reduction in size in the S. vehrascenais is more abrupt. The latter 

 species is said to be of Miocene age. 



December 15. 

 The President, Dr. Ruschenberger, in the chair. 

 Twenty-two members present, 



Remarks on Fossih 'presented. Prof Leidy remarked that the 

 collection of fossils presented this evening by Lieut. E. Crawford, 

 U.S.A., contained some interesting specimens. Among them 

 are a number of tartiary vertebrate remains, which were found l\y 

 Lieut. Crawford about ten miles from Red Cloud Agency, Ne- 

 braska. They mainly consist of fragments of bones and teeth, 

 similar to those which he had previously ascribed to Titanotheriura. 

 The s|)ecimens indicate two individuals differing in size. 



A lower jaw fragment, contains a last molar, like tiiose repre- 

 sented in Plate XVi. of the Ancient Fauna of Nebraska, except that 

 the external basal ridge is interrupted at the extreme outer part 

 of the lobes of the crovvn. The fore and aft diameter of the latter 

 has been about 3 inches and 7 lines. 'J he thickness of the jaw 

 just below the fore part of the tooth is little more than two inches. 



A number of lower molars exhibiting evidences of having 

 belonged together indicate a larger animal than the former. The 

 last molar has lost its hinder lobe, but without this is as large 

 fore and aft as in the specimen first indicated. When perfect, it 

 was about 4^ inches antero-posteriorl3\ In this likewise the basal 

 ridge is interrupted at the extreme outer part of the lobes of the 

 crown. The crown of the second molar, well-worn, is 35 lines 

 fore and aft. 



The three premolars have the same constitution as the molars, 

 and rapidly diminish in size, passing forward in the series. The 

 first premolar is 14 lines fore and aft ; the second is 19 lines; and 

 the third is 22 lines. 



