MAliYLxlND GEOLOGICAL SURVEY 11 



Peiscodelphinus lacertosus Cope. 



Belphirmpterus lacertosus Cope, 1868, Proc. Acad. Nat. Sci. Phila., vol. xx, p. 190. 

 Tretosphyx lacertosus Cope, 1868, Proc. Acad. Nat. Sci. Phila., vol. xx, p. 189. 

 Delphinapterus hawkinsi Cope, 1868, Proc. Acad. Nat. Sci. Phila., vol. xx, p. 190. 

 Tretosphys lacertosus Cope, 1869, Proc. Acad. Nat. Sci. Phila., vol. xxi, p. 7. 

 Tretosphys lacertosus Leidy, 1869, Jour. Acad. Nat. Sci. Phila., 2ud ser., vol. vii, p. 



434. 

 Friscodelphinus lacertosus Cope, 1875, Proc. Amer. Philos. Soc, vol. xiv, p. 863. 

 Priscodelphinus lacertosus Cope, 1890, Amer. Nat., vol. xxiv, p. 61.5. 



Description. — This species is described as "much the largest species 

 of the genus. It is based on two lumbar vertebrae which have been 

 united by exostosis and then separated. They are quite elongate and 

 have broad diapophyses so far as their bases indicate. The articular 

 faces are about as broad as deep, and slightly pentagonal in outline, 

 not ovoid or discoid as in other species. The lower surface presents an 

 obtuse median angle, with slightly concave sides.'' 



There were two specimens; one from the mouth of the Patuxent 

 river in Maryland consisting of a single vertebrae, and five others from 

 the marl pits near Shiloh in Cumberland county, New Jersey. The 

 type is in the museum of the Academy of Natural Sciences of Phila- 

 delphia. One of the vertebrae so preserved is labeled, on the speci- 

 men, Delphinapterus lacertosus, but the accompanying case label is 

 "Tretosphys lacertosus Cope. (Delphinapterus lacertosus. Cope.)" 

 Another specimen in the same lot bears the label " Delphinapterus 

 Hawkinsi = Delphinapterus lacertosus. Cope." 



Measurements of a vertebrae of 7'. lacertosus. 



Length centrum 3 in. 5.5 lines (85.5 mm.) 



Height articular surface 2 in. 2.5 lines (55 mm.) 



Width articular surface 2 in. 4.5 lines (59 mm.) 



Width neural canal .7.5 lines (15 mm.) 



Width base diapophysis 1 in. 9 lines (45 mm.) 



Occurrence. — St. Mary's (?) Formation. Mouth of the Patuxent 

 river. Calvert Formation. Charles county near the Patuxent river. 



Collection. — Philadelphia Academy of Natural Sciences. 



