NATURAL SCIENCES OF PHILADELPHIA. 313 



Spelerpes lineolus Cope, Proc. Acad. Nat. Sci. Philad. 18G5, 196. Ophio- 

 batrachus vermicularis Gray, Ann. Mag. N. Hist. 1868, 297. 



This species varies somewhat in the relative length of the tail. One of the 

 specimens from Cordova, Vera Cruz, measures as follows : head and body 17-3 

 lines ; tail 2 in. 10-4 lines. 



In the collections of the Smithsonian Institution. 



Grotriton carbonarius Cope. 



A uniformly black variety of this species occurs in the high lands of Guate- 

 mala, and another with two dorso-lateral ochre bauds is found in Yucatan. 

 Mus. Smithsonian, 



Dec. 1st. 

 The President, Dr. Hays, in the Chair. 



Thirty-five members present. 



The following papers were presented for publication : 



" Notice of some remains of extinct Insectivora from Dakota." 

 By Dr. J. Leidy. 



" Observations on Reptiles of the Old World. Art. II." By 

 Edw. D. Cope. 



" Notes on some points in the structure and habits of the Palse- 

 ozoic Crinoidea." By F. B. Meek and A. H. Worthen. 



Dr. Leidy exhibited some specimens of Mica recently received from West- 

 port, Canada, remarkable for the beauty and distinctness of its asterism, pror 

 duced by minute acicular crystals profusely scattered between the laminae. 

 The star exhibited twelve equidistant rays, exceeding in strength any previ- 

 ously seen by him in varieties of the mineral. 



Prof. Cope made some observations on some extinct reptiles of interest. 

 One of these, represented by a single sacro-caudal vertebra from Swedesboro', 

 N. J., indicated a second species of Elasmosaurus. It was of equal size with 

 the corresponding one of the Kansas specimens, but differed in the square and 

 uncontracted form of the centrum, and greatei stoutness of the diapophyses. 

 He called it E. orientalis. 



Another reptile was represented by a vertebra, tooth, and portion of mandi- 

 ble. It was a gavial-like crocodile, which if of proportions similar to those of 

 the Gangetic species, would indicate an animal of thirty feet in length. It 

 belonged to the genus Thecachampsa Cope, and was allied to the T. antiqua 

 {Crocodilus Leidy), but differed in the more compressed knife-like tooth crowns. 

 Miocene of Maryland. 



He also exhibited bones and teeth of a large Rodent from the cave deposits 

 of Anguilla, one of the Virgin West India Islands. The characters observed 

 were those of the genus Chinchilla, but the roots of the teeth were contracted 

 and not so open as in many Rodents, as though having a more limited period 

 of growth, or perhaps like deciduous teeth, which are much reduced in num- 

 ber in most Rodents. The species was nearly as large as the Castoroides o h i o- 

 en s i s of North America, but had relatively smaller incisor teeth. The body 

 was probably as large as that of the Virginia deer, and the limb bones as 

 stout, as seen in portions of femora and other pieces preserved. He called the 

 animal Amblyrhiza ixu.vdata, and thought that its discovery on so small an 

 island, with others of like character, indicated that the Carribean continent . 

 had not been submerged prior to the close of the Post-pliocene, and that its 

 connection was with other Antilles, while a wide strait separated it from the 

 then comparatively remote shores of North America. 



1868.J 21 



