78 SYSTEMATIC PALEONTOLOGY 



downwards; secondary cones usually six in number, all acutely pointed, 

 and attached to a deep, laterally compressed root, beveled on its outer 

 face. Principal teeth of the upper jaw less laterally elongated and with 

 fewer cusps than those of the lower jaw. Lower median tooth with 

 a well defined cusp. 



The teeth of this species are intermediate in character between those 

 of N. serratissimus, which are usually smaller, and N. gigas, which are 

 longer and have a larger number of secondary cones. The average 

 length attained by the lateral teeth is about 3 cm. Cope states of his 

 so-called N. pledrodon that " it presents fewer denticles than any other 

 species, and thus approaches distantly the N. recurvus of Agassiz." 

 Comparisons show, however, that both of these species are founded on 

 teeth referable to the upper jaw of N. primigenius. About a score of 

 specimens have been obtained in all from the Miocene of Charles 

 county. Plum Point and Fairhaven. The root is unfortunately injured 

 in the specimen shown in Plate XXIX, Fig. 6. 



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

 ent river. Plum Point, Fairhaven. 



Collections. — Maryland Geological Survey, Johns Hopkins University, 

 Philadelphia Academy of Xatnral Sciences, Museum of Comparative 

 Zoology. 



Family LAMNIDAE Midler and Henle. 



Genus ODONTASPIS Agassiz. 



Odontaspis cuspidata (Agassiz). 

 Plate XXX, Figs, la, lb. 



Lamna cuspidata Agassiz, 184.S, Poiss. Foss., vol. iii, p. 290, pL xxxvii a, figs. 43- 



50. 

 Odontaspis cuspidata Eastman, 1901, Md. Geol. Survey, Eocene, p. 105, pL xiv, figs. 



la, lb, 6a, 6b. 

 Lamna cuspidata Hay, 1903, Bull. 179, U. S. Geol. Survey, p. 302. 



This species occurs with rather less frequency in the Miocene than in 

 the Eocene of this state, and is found principally at Plum Point and 

 Fairhaven. All the examples observed are of the anterior dentition, 

 and in the majority of cases are more or less water-worn. 



Occurrence. — Calveet Foemation'. Charles county near the Patux- 

 ent river, Plum Point, Fairhaven. 



