Stewart.] Cretaceous Fishes. 311 



two genera from the specimens in the museum. Furthermore, 

 if Saurocephalus were removed to another family, Saurodon 

 would have to follow, as the two genera are too closely allied 

 to be far separated from each other, and the absence of the long 

 rostrum, paired and toothed predentary, and the presence of 

 more than one row of teeth on the maxillae and mandibles would 

 preclude any close relationship with the family to which he re- 

 fers it. I think the two genera should be placed in a distinct 

 family, as has been done above. 



Revised synopsis of the Saurodontidse : 



Foramina below the alveolar border internally. 



Teeth with short compressed crowns Saurocephalus. 



Deep notches below the alveolar border internally. 



Teeth with snbcylindric crowns Saurodon. 



SAURODON. 



Hays, Trans. Am. Phil. Soc, 1830, p. 476. 

 Cope, Proc. Acad. Nat. Sci. Phil., 1873, p. 339. 



In the year 1830, Doctor Hays 70 described the genus Saurodon 

 from a portion of a skull and jaws from the Marl of New 

 Jersey. He also examined the type specimen of Saurocephalus, 

 described by Doctor Harlan 71 six years before, and decided that 

 the two genera were synonymous, and, as Doctor Harlan's genus 

 was founded upon erroneous characters, the name Saurodon 

 should take precedence over it. In 185G Doctor Leidy 7:J rede- 

 scribed both of the above specimens and decided that the name 

 Saurodon should be abandoned and Saurocephalus used instead. 

 Nothing further was done with either of these forms until 1873, 

 when Professor Cope added the genus Dap! 'max, which he later 

 recognized as a synonym of Saurodon. 



The exact date of Professor Cope's retraction I have been un- 

 able to exactly determine, but it was probably not until after 

 1878, as during this year Mr. E. T. Newton 7 - described a fish 

 from the Lower Chalk of Dover and provisionally placed it in 

 Daptraus. A little later in the same year, Mr. Newton pub- 

 lished another paper 74 in which he carefully goes over the 



70. Trans. Am. Phil. Soc-., vol. Ill, p. 471. 73. Trans. Am. Phil. Soc., vol. XI, p. 91. 



71. Jour. Acad. Mat. Sri. Phil., vol. III. p. 881. 74. 1. c. No. 136, p. 786. 

 ~<>. Quart. Jour. QaoL Soc, 1>7\ No. 135, p. 439. 



