MARYLAND GEOLOGICAL SURVEY 29 



Delphinodon leidyi (Hay). 

 Plate XA'I, Figs. 3, 4, 5. 



Phoca wymani Leidy, 1856, Proc. Acad. Nat. Sci, Phila., voL viii, p. 26.5. 

 Sqnalodon ivymani Cope, 1867, Proc. Acad. Nat. Sci. Phila., voL xix, pp. 151, 152 



[not p. 132). 

 Delphinodo7i wymani Leidy, 1869, Jour. Acad. Nat. Sci. Phila., 2nd ser., voL vii, p. 



425, pi. XXX, tig. 10. 

 DeIphinoclo7i wymani Cope, 1890, Amer. Nat., vol. xxix, p. 614. 

 Delphi7iodon leidyi Hay, 1902, Bull. 179, U. S. Geol. Survey, p. 591. 



Description. — " One of the teeth (pi. xxx, fig. 10) bears a resem- 

 blance to the first described of the large species (mento). 



" Its crown is proportionately longer, and the posterior tubercle and 

 internal curved ridge of the crown are rudimental, but it has the same 

 general form, with the abrupt curvature and slight twists of the summit 

 backward and inward. The ridges defining the inner and outer sur- 

 faces of the crown are alike in their course and the enamel is likewise 

 wrinkled. 



" The fang has the same form but is comparatively less curved. 



"Length of fang 5 lines (10 mm.); breadth 3f lines (7.5 mm.); thick- 

 ness 3 lines (6 mm.)" 



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

 ent river. 



Collection. — The type is in the Museum of the Academy of Natural 

 Science of Philadelphia. 



Family DELPHINIDAE. 



This family differs from the foregoing in the anchylosis of the cervi- 

 cal vertebrae; in the shortness of the nose which is never developed 

 into a rostrum of any length; in the shortness of the symphysis which 

 never exceeds one-third the length of the Jaw. The teeth are usually 

 simple and very numerous in both jaws but may be reduced to a single 

 greatly elongated tooth in the upper jaw as in the male of the Narwhal 

 (Monodon). To this family belong the common Porpoise (Phocoaena), 

 the Dolphin (Delpliinus), the Killer Whale (Orca) and many other 

 living forms. 



No members of this family have been described from the Miocene 

 beds of Maryland. 



