NORTH-CAROLINA GEOLOGICAL SURVEY. 



237 



It differs from the former in the character of the enamel, 

 curvatures, the absence of serratures.. 

 and the form and development of its 

 root. 



PIG. 67. 



GENUS GALEOCERDO. AGASS. 



This genus is an inhabitant of our 

 present seas, and the species arcticus 

 (Fig. 49) very closely resembles the 

 galeocerdo aduncus, whose teeth are 

 abundant in the miocene marl beds 

 of North-Carolina. In both jaws the 

 teeth are similar and equal. They form 

 five rows, which contain twenty-three 

 teeth each, an odd small tooth occu- 

 pying a middle position over the sym- 

 physis. The back teeth become small and are relatively 

 shorter than the side teeth, presenting in this respect 

 an approach to the form of the teeth described as the 

 galeocerdo latidens. In two species of galeocerdo which dif- 

 fer in size, the serratures are constant and preserve a great 

 uniformity; and the common character of the serratures 

 seems to be, that which might be called compound, by which 

 I mean, that each notch is itself notched, and it is possible 

 that many of the species possessed this character more or 

 less, but have lost it by wear in their usage. 



Figure 49 shows the arrangement of the front teeth of the 

 lower jaw in the galeocedo arcticus, and the position of a small 

 series of teeth immediately above the simphysis. 



GALEOCERDO ADUNCUS. AGASS. 



Tooth oblique angulated, and winged on one side, or with 

 the sides unequal. Anterior face convex, posterior rather 

 flat. Serrate, serratures unequal, the first upon the wing the 

 largest ; upon the arched edge the serratures are largest upon 

 the lower half of the crown. 



