ELASMOBRANCHII. 67 



on outer margin. Spiracles present. First dorsal opposite space 

 between pectorals and ventrals. Caudal with double notch. Pit 

 on tail above and below at caudal base. 



Among existing species large sharks in most seas, referred to 

 about four species. About 30 fossil species have been described. 



Galeocerdo aduncus Agassiz. 



Galeocerdo aduncus Cope, Proc. Amer. Philos. Soc. Phila., XIV, 1875, p. 362. 

 (Cumberland Co. Miocene.) 



Teeth compressed, broad, elevated, and rather thin. Coronal 

 surfaces rather low, compressed, smooth, broad, pointed, and 

 inner slightly more convex than outer, which is somewhat flat- 

 tened in most cases. Apex usually deflected greatly to one side, 

 and longer coronal margin mostly forming a very obtuse angle, 

 sometimes nearly evenly convex. Cutting-edges finely serrated. 

 Margin below notch with graduated serrse, those at notch largest, 

 and generally at least four more conspicuous. No basal cusps. 

 Root broad, compressed, deep internally and moderately convex, 

 and externally rather concave and shallow. Lower margin usu- 

 ally moderately emarginate. Length 18 mm. 



This species seems to be close to Galeocerdo contortus, and 

 appears to differ chiefly in the coronal apex of the teeth, being 

 flatly compressed and broad. According to Woodward, it closely 

 resembles the living Galeocerdo arcticiis in the dentition, but the 

 teeth are smaller. I have identified the material here listed to 

 some extent provisionally. 



Formation and location. Known from upper Cretaceous and 

 Miocene, where most likely the following were obtained : "New 

 Jersey" 2 (Burtt) ; Monmouth County 3 (P. D. Knieskern), 3 

 (W. Cleburne) ; Deal 1 (W. A. Powell) ; Shark River Miocene 

 3 (T. A. Conrad) ; Burlington County 4 (Conrad) ; Vincen- 

 town 2 (T. M. Bryan) ; Allowaystown in Salem- County 1 with- 

 out donor. 



In the Geological Survey collection is a single tooth from the 

 middle marl of Riddleton (Hackett's pits). [From the above 



