176 PROCEEDINGS OF THE ACADEMY OF 



September I2ih. 



The President, Dr. Bridges, in the Chair. 



Eighteen members present. 



The deaths of Mr. Jacob R. Smith and Mr. Joseph D. Brown, mem- 

 bers of the Academy, were announced. 



September 19th. 



The President, Dr. Bridges, in the Chair. 

 Twenty members present. 



The following papers were offered for publication : 

 " On a new generic type of Sharks," and " On two species of Del- 

 phinidae." By Prof. Theo. Gill. 



" Notes on a species of Hunchback Whale." By Prof. E. D. Cope. 



Dr. Leidy directed the attention of the Academy to some fossil remains of 

 Rhinoceros from Texas and California, which, he observed, together with those 

 already described by him from the Mauvaises Terres of White River, and from 

 the Niobrara or L'eau-qui-court River, of Nebraska, were probable evidence of 

 the former existence of five species of the genus within the boundaries of the 

 United States. 



One of the species, previously described, from White River, is so peculiar as 

 to constitute a subgenus apart from the others. It was a small animal, with a 

 hornless skull, and possessed six incisors and a pair of canines in each jaw, 

 besides the usual series of seven molars on each side. It was named Hyraco- 

 don nebraskensis (Proc. Acad. Nat. Sci. 1856, 92.^ 



The second species, Rhinoceros occidentalism from White River, has the same 

 formula of dentition as the Indian or Javan Rhinoceros, and was about half 

 the size of that animal. 



Rhinoceros crassus, (Pr. Ac. 1858, 28), from L'eau-qui-court, has the same 

 formula of dentitiou as the Indian Rhinoceros, and was about the same size. 

 The incisors appear to have held the same proportionate size as in the latter, 

 but in R. occidcnlalis they were proportionately very much smaller. A worn 

 superior incisor of R. crassus measures 28 lines antero-posteriorly and 10 lines 

 transversely. The corresponding tooth of R. occidentals measures 11 lines by 

 5 lines. A broken superior last molar of the former is estimated to have 

 measured 28 lines obliquely and externally, the same diameter transversely 

 and anteriorly, and 24 lines antero-posteriorly and internally. In R. occidentalis 

 corresponding measurements hold the relationship of 18 lines, 18 lines, and 16 

 lines. 



The Texan Rhinoceros is indicated by the greater and more characteristic 

 portion of the crown of an upper molar tooth, probably the penultimate. It 

 was obtained from a tertiary deposit, probably miocene, and submitted to Dr. 

 L. for examination, by Dr. Benj. F. Shumard. It presents much the general 

 appearance of preservation of the Mauvaises Terres fossils of White River. It 

 evidently indicates a species different from those of the latter locality, and 

 was larger than either, approaching in size R. crassus, though it was smaller. 

 The estimated measurements of the restored tooth are two inches for the an- 

 tero-posterior diameter externally, 22 lines for the transverse diameter ante- 

 riorly, and 18 lines in the latter direction posteriorly. The median valley is 

 strongly sigmoid, arising from each of the inner lobes being provided with an 

 oblique offset extending into the valley in a parallel manner. For the species 

 the name of Rhinoceros meridianus was proposed. 



The California Rhinoceros is indicated by the greater portion of the right' 



[Sept. 



