Cope.] t)Uy [Nov. 18, 1870. 



NOTE ON SAUROCEPHALUS, HARLAN. 

 By E. D. Copk, in the Meeting November 18, 1870. 



Prof. Cope called attention to the cretaceous group of fishes represented 

 by Saurocephalus of Harlan. Pie said they had been regarded as related 

 to the Acanthopterygian family of SpJiyrcenidce. 



He showed that they were more like certain Malacopterygian families in 

 the structure of the mouth ; that the neural arches of the vertebras were 

 not coossified ; and that the tail was vertebrated in a manner between 

 the types of Salmonidoi and Amiidce. He said the pectoral rays of the 

 group had been described by Leidy under the name of XipJiactinus, and 

 that the caudal rays were remarkably and beautifully segmented. He 

 said that they had been hitherto regarded by authors as spines or rays of 

 tlae cestraciont genus Ptychodus. 



Prof. Cope also made a communication on the results of the explora- 

 tions of certain caves in the island of Anguilla in the West Indies, by 

 Dr. Van Rijgersma. He stated that the vertebrata embraced eleven 

 species, of which one was a Crocodilian, two birds, one a deer, and five 

 rodents. Of the latter, three were of gigantic size, including, beside the 

 two species of Chinchillas already described (Proceed. Amer. Philos. Soc, 

 1869, ISij), a third, larger than either, which was named Loxomylus lati- 

 dens, Cope. It differed from the L. longidens, Cope, in having teeth with 

 triturating surface less oblique to the axis of the tooth, and wider than 

 long, instead of longer than wide, and with a certain irregularity in the outer 

 margin. The distal end of the femur measured 3^ inches across ; the se- 

 ries of superior molars 2^ inches ; width of two inferior incisors in place 

 one inch and two lines. The bones of the deer indicated a species a little 

 over half the size of the Chinchilla. 



