so SYSTEMATIC PALEONTOLOGY 



Description. — "^Anterior teeth narrow, much elevated, and robust; 

 crown much curved inwards, the outer coronal face nearly flat, the 

 inner very convex; root with two elongated branches diverging at an 

 acute angle. Lateral teeth more compressed, with a shorter root having 

 more divergent branches; crown narrow, the cutting-edges in most 

 cases gradually diverging to the extremities of the base, and the apex 

 rarely reflexed." — Woodward. 



The original of Plate XXX, Fig. 4, is an average-sized specimen of 

 the anterior series of teeth; it belongs to the Museum of the Philadel- 

 phia Academy of Natural Sciences. 



Occurrence. — Calvekt Formation. Plum Point, Charles county 

 near the Patuxent river. 



Collections. — Maryland Geological Survey, Philadelphia Academy of 

 Natural Sciences, Museum of Comparative Zoology, 



OxYRHiNA hastalis Agassiz. 

 Plate XXX, Figs. 5a, 5b, 6a, 6b, 6c. 



Oxyrhina hastalis Agassiz, 1843, Poiss. Foss., voL iii, p. 277, pL xxxiv, {excl. figs. 



1, 2, ? 14). 

 Oxyrhina hastalis Eastman, 189.5, Palaeoutogr., vol. xli, p. 178 (complete literature 



references and syonymy). 

 Oxyrhina hastalis Clark, 189.5, Johns Hopkins Univ. Circ, vol. xv, p. 4. 

 Oxyrhina hastalis Clark, 1896, Bull. 141, U. S. Geol. Survey, p. 42. 

 Isurus hastalis Hay, 1902, Bull. 179, U. S. Geol. Survey, p. 306. 



Description. — "Teeth attaining a large size, broad, thin, compressed; 

 outer coronal face flat or concave, rarely with vertical wrinkles; root 

 short, the branches very divergent, usually blunt and abbreviated. 

 Anterior teeth large, triangular and relatively broad, the crown only 

 gently curved outwards at the apex; coronal edges of the lateral teeth 

 gradually curving to the extremities of the base, the apex often bent 

 slightly outwards." — Woodward. 



The teeth of this species are rather more abundant than those of 

 0. desorii, which accompany it at Plum Point and in Charles county. 

 The example figured is from the former locality, and is one of the 

 largest lateral teeth in the collection, its total height being very nearly 

 6 cm. 



