20 SYSTEMATIC PALEONTOLOGY 



There are mentioned as belonging to this form 3 dorsals, 9 lumbo- 

 sacrals and 1 caudal, not necessarily belonging to the same individual; 

 of these only a portion are preserved in the museum of the Academy 

 of Natural Sciences of Philadelphia. The others seem to be lost. 



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

 ent river. 



Collection. — Philadelphia Academy of Natural Sciences. 



Genus ZARHACHIS Cope. 



Zarhachis flagellator Cope. 

 Plate XIV, Fig. 3. 



Zarhachis flagellator Cope, 1868, Proc. Acad. Nat. Sci. Phila., voL xx, p. 189. 

 Zarhachis flageUator Cope, 1809, Proc. Acad. Nat. Sci. Phila., vol. xxi, p. 9. 

 Zarhachis flagellator Leidy, 1869, Jour. Acad. Nat. Sci. Phila., 2nd ser., vol. vii, p. 



435 (niention only). 

 Zarhachis flagellator Cope, 1890, Amer. Nat., vol. xxiv, p. 614. 



Description. — In 1869 Cope gave the following description of the 

 genus : " This genus is established on vertebrae which bear a general 

 resemblance to those of Priscodelphinus, but differ in the essential point 

 of having flat and broad diapophyses of the caudals. It is therefore 

 intermediate between that genus and Delphinapterus. The posterior 

 caudals in our museum exhibit a narrowing of the diapophyses, as in 

 certain of the lumbars do in Priscodelphinus. 



" All these vertebrae are of a greater length as compared to the 

 diameter than in any cetacean known by me except the great Basilo- 

 saurus. The lumbars, when compared with those of T. (Tretosphys) 

 lacertosus, differ in their broadly obtuse median line, which offers dis- 

 tinct traces of two keels. An anterior caudal either exhibits unusually 

 broad diapopliyses, which are directed downwards, or else is a lumbar 

 with two keels, and a median groove below, which is not seen in any 

 other species. The caudals exceed in length those of any other species. 

 One of these, from a large individual, resembles P. atropius in the 

 narrow basis of the diapophysis, which is probably narrow, and not 

 perforate. The length of the vertebra is nearly double the vertical 

 depth of the articular faces. The diapophysis is nearly median; the 

 basis of each neurapophysis is one-half the length of the centrum and 

 median. 



