SCYMNORHINID^E^SCYMNORHINUS 23 



There probably have been four distinct species of the Great White 

 Sharks in California, one of these (CARCHARODON c ARCH ARIAS') still 

 living. 



These may be thus distinguished : 



a. Base of tooth on each side with a serrated protuberance or 

 denticle tip of tooth without serrations ; serrations 50 to 60 on each side. 

 Miocene of Kern County. RECTUS. 



aa. Base of tooth without denticle ; tip of tooth serrate, like the sides. 



b. Serrations few, mostly 20 to 50 on each side ; teeth small, less than 

 3 inches high. 



c. Species living; serratiqns 20 to 40; teeth relatively narrow. 



CARCHARIAS. 



cc. Species extinct; teeth broader; serrations 30 to 40 (RIVERSI), 45 

 to 50 (ARNOLDI). ARNOLDI. 



bb. Serrations 80 or more; teeth broad, 4 to 7 inches long. (Ser- 

 rations 80 to 90, very fine, BRANNERI, or 100 to 120, rather coarse; MEGA- 



LODO N . ) M EGALODO N . 



Family SCYMNORHINID^. 

 14. Scymnorhinus occidentalis (Agassiz). 



Of Kern Miocene. This genus should apparently stand as .SCYM- 

 NORHINUS. SCYMNUS is preoccupied and the type of DALATIAS is prob- 

 ably a species of CENTROPHORUS. 



Family ECHINORHINID^E. 



15. Echinorhinus blakei Agassiz. 



Of Kern Miocene. I have seen no teeth referable to this genus. 



Family SQUATINID^. 



16. Squatina lerichei Jordan and Beal. 



(Plate VII, fig. E) 

 Of Kern Miocene. 



Family MYLIOBATID^. 

 17. Myliobatis merriami Jordan and Beal. 

 Of Kern Miocene. 



18. Rhinoptera smithi Jordan and Beal. 

 Of Kern Miocene. 



Family PHOLIDOPHORIDJE. 



19. Ganolytes clepsydra Jordan and Gilbert, new species. 



(Plate XI, fig. 1) 



Type a specimen (VI) from El Modena, Hadley collection, 7 or 8 

 inches long in life. Head about 3% in length to base of caudal ; depth, 



