DISCOVERY OF THE TITANOTHERES AND ORIGINAL DESCRIPTIONS 



235 



Etymology. — Named in honor of Prof. John M. 

 Tyler, of Amherst College, "a teacher of men, who, 

 by his earnest efforts, as well as by his own generosity, 

 was mainly instrumental in maldng possible the ex- 

 pedition which secured the specimen" (Lull). 



Present determination. — This species is probably 

 valid. It is discussed on page 502 of this monograph. 



Figure 198. — Type (holotype) skull of Brontotherium leidyi 



After Osborn, 1902. Nat. Mus. 4249. One-eighth natural size. The side view of this 

 skull was figured by Marsh (Am. Jour. Soi., October, 1887) as Menops varians. 



SPECIES DESCRIBED BY OSBORN IN 1908 

 Brontotherium hatched Osborn, 1908 



Cf. Brontotherium hatcheri, this monograph, page 563 



Original reference. — Am. Mus. Nat. Hist. Bull., vol. 

 24, pp. 615-616, fig. 20, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — South Dakota; 

 Chadron formation, middle Titanotherium zone (Chad- 

 ron B), lower levels. J. B. Hatcher, collector. 



Type. — A nearly complete skull (Nat. Mus. 1216, 

 skull a) lacking the premaxillaries and anterior por- 

 tion of the maxillaries. (See fig. 202.) 



Specific characters. — Osborn writes: 



If, Pf. Nasals moderately long (97 mm.), thin at the 

 edges. Horns 250 -f millimeters, two-thirds the length oj 

 B. gigas horns. Skull length (pm.x-condyles) , 710 (estimated), 

 width across zygomata, 530 (estimated) . This species appears 

 to represent an early phase of evolution of B. gigas. The horns 

 are very round or convex in section and have a well-defined 

 malar ridge on the lower outer portion. The connecting crest 

 is relatively shallow, and the nasals are thin. The premolars 

 are well advanced, the tetartocone of p' being well rounded and 

 quite distinct. 



Etymology. — Named "in honor of the late J. B. 

 Hatcher, who discovered many of Professor Marsh's 

 titanothere types, brought together the great collec- 

 tion of titanotheres ia the National and Yale Mu- 



seums, and placed the stratigraphic succession of the 

 species upon a secure basis." (Osborn.) 



Present determination. — The species is probably 

 valid. 



Symborodon copei Osborn, 1908 



Cf. Megacerops copei Osborn, this monograph, page 548 



Original reference. — Am. Mus. Nat. Hist. Bull., vol. 

 24, pp. 616, 617, fig. 21, 1908 (Osborn, 1908.318). 



Type locality and geologic horizon. — South Dakota, 

 Big Badlands, Indian Draw; Chadron formation, 

 level probably middle Titanotherium zone (Chadron 

 B). J. B. Hatcher, collector. 



Type. — A complete skull (Nat. Mus. 4711, skull 

 V), collected by J. B. Hatcher, 1888. (See fig. 203.) 



Specific and generic characters. — Osborn writes: 



Incisors (type) persistent but greatly reduced; canines 

 very small, reduced (28 mm.) ; premolars with cingula reduced 

 or absent; tetartocones connected with deuterocones by a 

 longitudinal ridge. Skull: nasals thin, short and broad in pro- 

 portion, 80 by 125 millimeters; horns, S , 300, no connecting 

 crest, transverse oval near summit; buccal processes of zygomata 

 t? stout and conve.x; malar in front of buccal process very deep, 

 beneath postorbital process stout, convex; occipital pillars 

 not greatly expanded at the summits. 



Etymology. — Named in honor of the late Prof. 

 E. D. Cope, prolific author of "The Vertebrata of the 

 Tertiary formations of the West," original describer of 

 Symborodon, founder of the "Cope collection," now 

 in the American Museum of Natural History. 



Present determination. — The species is probably 

 valid. 



CANADIAN SPECIES DESCRIBED BY LAMBE IN 1908 

 Megacerops primitivus Lambe, 1908 



Cf. Teleodus primitivus, this monograph, page 482 



Original reference.— Contr. Canadian Paleontology, 

 vol. 3, pt. 4, pp. 49-51, pi. 6, figs. 4, 5, 1908 (Lambe, 

 1908.1). 



FiauRE 199.^Upper premolars of type 



skull of Brontotherium leidyi 



After Osborn, 1902. Nat. Mus. 4249. One-halt natural size. 



Type locality and geologic horizon. — "Oligocene 

 deposits of the Cypress Hills," Saskatchewan. Col- 

 lector, L. M. Lambe, 1904. 



Type. — Both halves of the lower jaw, with the denti- 

 tion of the left side complete. Ottawa Museum. (See 

 fig. 204.) 



Specific characters. — Lambe writes: 



Incisors, in three pairs, with a space between the inner pair; 

 canines, of small diameter, apparently short; a diastema 



