122 THE COAL MEASURES AMPHIBIA OF NORTH AMERICA. 



The posterior outline of the skull in the present specimen is not well preserved 

 and the outline as given may be slightly inaccurate. The indentation figured by 

 Jaekel in the posterior border of the skull of the type form is not present in the 

 species under discussion. 



Measurements of the Type Skull of Diceratosaurus LiEvis Moodie. 



mm, mm. 



Length of skull along median suture 37 Width of skull across the orbits 30 



Length from muzzle to tip of horn 50 Interorbital width 6 



Width between tips of horns, estimated 40 Length of nostril opening 2 



Width of orbit 7 Width of nostril I 



Lntgth of orbit 10 Diameter of the pineal foramen — I 



Diceratosaurus robustus Moodie. 



Moodie, Jour. Geol., xvii. No. i, p. 67, fig. 15, 1909. 



Moodie, Bull. Am. Mus. Nat. Hist., xxvi, art. xxv, p. 355, pi. Ixiii, fig. 2, 1909. 



Type: Specimen No. 86 ii G, American Museum of Natural History. 



Horizon and locality: Linton, Ohio, Coal Measvires. 



The present species is indicated by the left portion of a cranium representing a 

 large individual. The characters of the skull are so clearly marked that it seems 

 worthy of description. The presence of horns as given in the restoration of the 

 skull (fig. 24, B) is based on the analogy with the other two species of this genus, in 

 both of which horns are present. The generic determination of the species is based 

 on the large size of the postorbital, which is essentially characteristic of the other 

 species of Diceratosaurus. 



The characters which distinguish the species from others of the genus are the 

 large postorbitals and the small parietals, which are excluded from union with the 

 postfrontals on account of the large size of the frontal. In the other two known 

 species the frontal is small and the parietal comes forward to join the postfrontal. 

 The present species exhibits a skull which is nearly twice as large as that of D. 

 IcEvis and nearly three times the size of the skull of D. punctolineatus. 



The portion of the skull preserved shows the cranium to have had a rather acu- 

 minate snout, not blunt as in the type species. The orbit is an elongate oval, 

 although it has the same relative position in the skull as in the other species. The 

 nostril is indicated by an oval depression near the anterior edge of the skull. The 

 frontals, as indicated by the sutures present on the portion of the skull which is 

 preserved, are fully as long as the parietals. Whether they were as wide as is repre- 

 sented is uncertain. The postfrontals are very small bones, the sutures of which 

 are somewhat uncertain, although they can not be far from what is represented 

 (fig. 24, B). The postorbital is large and elongate, and is distinctive of this species on 

 account of its unusual size, although it does not attain the same proportions as in 

 other members of the genus. The parietals are elongate and narrow. The pineal 

 foramen is represented by its lateral edge and its position is about midway of the 

 longitudinal diameter of the parietals. The narrow postparietal is represented by 

 its anterior border; as restored (fig. 24, B) it may be too long. The tabulare, also, is 

 represented by an anterior portion and it shows this element to have the position 

 and form which is typical of the form Diceratosaurus Icevis. Such other of the 

 cranial elements as are indicated are based on the relations discovered in D. lewis. 



