MAEYLAND GEOLOGICAL SUKVEY 23 



Genus CETOPHIS Cope. 



Cetophis heteroclitus Cope. 

 Plate Xiy, Fig. 4. 



Cetophis heteroclitus Cope, 1868, Proc. Acad. Nat. Sci. Phila., vol. xx, p. 185. 

 Cetophis heteroclitus Leidy, 1869, Jour. Acad. Nat. Sci., 2nd ser. vol. vii, p. 431 



(mention only). 

 Cetophis heteroclitus Cope, 1890, Amer. Nat., vol. xxiv, pp. 603, 606. 



Description.— This genus and species were founded upon caudal verte- 

 brae. " They present an approximation to Basilosaurus in the great 

 thickness of their epiphyses. In the more elongate vertebrae each 

 epiphysis will measure the third in length of the centrum deprived of 

 tliem; in the less elongate, they measure one-half the same; in the 

 shortest, more than half the remaining centrum. One extremity of 

 the vertebra is fiat, the other strongly convex, and none have any 

 trace of diapophyses." . . . "In two vertebrae, the longest and the 

 shortest, the foramina which usually pierce the sides of the centra 

 vertically, issue below, within the basal groove and above, below and out- 

 side the basis of the neurapoph^^sis. In another specimen the foramen 

 opens outside the inferior sulcus, and in one there is no foramen at all." 



The original description of the species is as follows: "The longer 

 or proximal caudal is subhexagonal in section, the median depressed 

 and the smallest round in section. The larger median is nearly round 

 in section. The epiphysis instead of retreating before a process of the 

 centrum opposite the four apophyses, as in Ixacanthus, advances on the 

 centrum at these points. The inferior groove is deep on the first and 

 shallower on the succeeding; obsolete on the last. 



Length smallest 2 in. 1 line (49 mm.) 



Length without epiphyses 11 lines (22 mm.) 



Height flat extremity 1 in. 10.5 lines (45 mm.) 



Width flat extremity 1 in. 11 lines (46 mm.)" 



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

 ent river. 



Collection. — Only one specimen of the type the smallest vertebrae is 

 preserved. It is in the Museum of the Academy of Natural Sciences 

 of Philadelphia. 



