DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



213 



Type locality. — Cedar Creek, Logan County, Colo. 



Type. — A cranium with premolar-molar teeth, zygo- 

 matic arches fractured (Am. Mus. 6350). (See figs. 

 170, 171.) 



Characters of type (summarized from Cope). — Nasal 

 bones very short, broad, obtuse, massive, and "stand- 

 ing on a plane above that of the front." Orbit very 

 far forward. Horns straight, with approximated bases 



Present determination. — As shown (p. 545), there are 

 reasons for regarding the type of S. altirostris as repre- 

 senting a female skull of Megacerops acer. 



Symborodon trigonoceras Cope, 1873 



Cf. Menodus trigonoceras, this monograph, page 528 



Original reference. — Synopsis of new Vertebrata from 

 the Tertiary of Colorado, p. 13, 1873 (Cope, 1873.3). 



and moderately divergent, subcylindrical at base and 

 compressed inward and forward at the narrow apex. 

 "The first premolar and two incisors are very insig- 

 nificant; canines with short stout crowns." The pre- 

 molars with two smooth cones. Many other charac- 

 ters are given. 



Etymology. — altus, high; rostris, beak, snout; in 

 allusion to the high position of the nasals. 



FiGUEE 168. — Type (holotype) skull of Megaceratops heloceras 

 Am. Mus. 6360. After Cope. One-flfth natural size. 



Subsequent references. — Cope, Eeport on vertebrate 

 paleontology of Colorado, 1874, p. 488, 1874 (Cope, 

 1874.2); The Perissodactyla, p. 1065, figs. 29, 30, 1887 

 (Cope, 1887.1). 



Type locality and geologic Tiorizon. — ^Horsetail Creek, 

 northeastern Colorado; Chadron formation {Titano- 

 therium zone), level not ascertained. 



