90 SYSTEMATIC PALEONTOLOGY 



it as a distinct species, although its description was for some reason 

 omitted. Possibly this is the same specimen which is listed as " Galeo- 

 cerdo ? sp. aff. contorto " in connection with his description of G. 

 laevissimiis^ What species is meant by his citation in the same place 

 of the nomen nudum, " GaJeocerdo appendiculatus Ag." cannot now be 

 even conjectured, as there are no specimens in the collection bearing 

 that designation. 



Occurrence. — Calvert Formation. Charles county near the Patux- 

 ent river. 



Collection. — Philadelphia Academy of Natural Sciences. 



Genus HEMIPRISTIS Agassiz. 



Hemipristis serra Agassiz. 

 Plate XXXIl, Figs. 13a. 13b, 14a, 14b, lie. 



Hemipristis serra Agassiz, 1843, Poiss. Foss., vol. iii, p. 287, pL xxvii, figs. 18-30. 

 Hemipristis serra Gibbes, 1849, Jour. Acad. Nat. Sci. Phila., 3nd ser., vol. i, p. 193, 



pi. XXV, figs. 75-85. 

 Lamna (Odontaspis) hopei Gibbes (non Agassiz), 1849, Jour. Acad. Nat. Sci. Phila. 



2nd sen, vol. i, p. 198, pi. xxvi, figs. 120-123. 

 Hemipristis heteropleurns Agassiz, 1856, Rept. Pac. R. R. Explor. and Survey, vol. v, 



p. 315, pi. i, tig. 14. 

 Hemipristis heteropleurns Agassiz, 1856, Amer. Jour. Sci., ser. ii, vol. xxi, p. 274. 

 Hemipristis serra Emmous, 1858, Rept. N. Car. Geol. Survej', p. 235, fig. 63. 

 Hemipristis crenulatus Emmons, 1858, Rept. N. Car. Geol. Survey, p. 235. 



Description. — " Marginal serrations in the broad upper teeth large, 

 extending almost to the apex, which is gently curved backwards. Cut- 

 ting edges of the anterior lower teeth very sharp distally. Inner face 

 of the root bulging inwards, with a deep cleft."' 



This easily recognized species occurs in considerable abundance in 

 the Eocene of South Carolina and Miocene of more northernly regions, 

 extending as far as the clitfs of Gay Head on Martha's Vineyard. The 

 lateral teeth are broad-based, strongly elevated along the middle of 

 the inner face, and prominently serrated along the lateral edges. The 

 serrations are oblique, rather more prominent on the posterior cutting- 

 edge than on the anterior, and increase in size from the base of the 

 crown to a point near the apex, where they cease altogether. 



iProc. Acad. Nat. Sci. Phila., vol. xix, 1867, p. 141. 



