100 THE CERATOPSIA. 



forms from Converse County, Wyo. The affinities of Monoclonius, as shown in the type species 

 M. crassus Cope and in M. dawsoni of Lambe, are apparently with the later genus Tricera- 

 tops of Marsh, while Ceratops montanus Marsh, 0. recur mcornis Cope, C. canadensis, and C. belli 

 Lambe would seem to be ancestral to Torosaurus. These questions will be more fully discussed 

 when we come to treat of the phylogeny and taxonomy of these dinosaurs. 



GENERA AND SPECIES DESCRIBED BY PROFESSOR MARSH FROM THE JUDITH RIVER BEDS. 



CERATOPS a Marsh. 1888. 



Type species, C. montanus. 



Original description in Am. Jour. Sci., 3d ser., vol. 36, Dec, 188S, pp. 477-478. 

 Marsh, O. C, ibid., Apr., 1889, pp. 327, 334-335; Aug., 1889, p. 175; Dec, 1889, pp. 505, 506; Jan., 1890, pp. 81-83; Feb., 



1891, pp. 171, 176; Apr., 1891, pp. 340-341; Sept., 1891, p. 266; Jan., 1892, p. 83; Dec, 1895, p. 497; Sixteenth Ann. 



Rept. U.S. Geol. Survey, 1896, pt. 1, pp. 145, 206, 210, 216, 219, 243. 

 Ed. Am. Geologist, vol. 8, 1891, p. 56. 



Baur, G., Science, vol. 17, 1891, p. 216; Am. Naturalist, vol. 24, 1890, p. 570; Am. Naturalist, vol. 25, 1891, p. 450. 

 Hatcher, J. B., Am. Naturalist, vol. 30, 1896, p. 113. 

 Lydekker, R., Nature, vol. 48, 1893, p. 304. 

 Nicholson and Lydekker, Manual Pal., 1889, vol. 2, p. 1163. 

 Nopcsa, F. Baron, Foldtani Kozlony, Budapest, 1901, vol. 31, p. 270. 

 Osborn, H. F., Contr. Canadian Pal., vol. 3 (quarto), pt. 2, 1902, pp. 9, 20. 

 Woodward, A. S., Outlines Vert. Pal., pp. 213, 216. 

 Zittel, K. A. von, Text Book Pal., trans, by C. R. Eastman, vol. 2, p. 245. 



The present genus may be distinguished from- Monoclonius Cope, based on material from 

 the same beds in Montana, by the greater development of the supraorbital horn cores, the longer 

 and narrower squamosals, the enlarged fontanelles, by which the parietals are reduced to slen- 

 der median and lateral bars. The nasal horn cores are very probably quite different also in 

 the two genera, though we can not as yet be certain as to their character in Ceratops. From 

 our present knowledge of the skull of Ceratops it seems to have been a precursor of Torosaurus 

 Marsh, while Monoclonius Cope appears to have been ancestral to Triceratops Marsh. 



Ceratops montanus Marsh. 1888. 



Type (No. 2411, U. S. National Museum) consists of occipital condyle and pair of frontal horn cores. 



Original description in Am. Jour. Sci., 3d ser., vol. 36, 1888, pp. 477—478. 

 Hatcher, J. B., Am. Naturalist, vol. 30, 1896, p. 113. 

 Marsh, O. C, Am. Jour. Sci., vol. 37, Apr., 1889, p. 327; Jan., 1890, p. 83; vol. 43, 1892, p. 84; Sixteenth Ann. Rept. U. S 



Geol. Survey, pt. 1, p. 216. 

 Nopcsa, F. Baron, Foldtani Kozlony, Budapest, 1901, vol. 31, p. 270. 

 Osborn, H. F., Contr. Canadian Pal., vol. 3 (quarto), pt. 2, 1902, pp. 9, 14, 18, 20. 

 Walcott, C. D., Science, new ser., vol. 11, 1900, p. 23. 



In December, 1888, Professor Marsh described the new genus and species Ceratops mon- 

 tanus. The type (No. 2411, U. S. National Museum) consists of an occipital condyle and a 

 pair of frontal horn cores, found together and pertaining to the same skull. These remains 

 were found by me in 1888. The horizon was near the top of the Judith River beds, and the 

 exact locality was on the northwestern slope near the summit, about 300 yards from the point 

 of the first hogback that projects into the valley of Cow Creek from the west, just below where 

 the old Cow Island and Fort Benton freight road descends into the valley of Cow Creek, about 

 10 miles above the confluence of that stream with the Missouri River. 



Marsh's original description of the above genus and species was as follows: 



The present genus appears to be nearly allied to Stegosaurus of the Jurassic, but differs especially in having had a pair 

 of large horns on the upper part of the head. These were supported by massive horn cores firmly coossified with the occipital 

 crest. The latter are probably attached to the parietal bones, but, as the sutures in this region are obliterated, they may 

 be supported in part by the squamosals. 



a The name Ceratops was used by Rafinesque in 1815 to designate a genus of birds. As no description of the genus was published, and as 

 no forms were mentioned as pertaining to it, it becomes a nomen nudum. Should expert nomenclaturists decide that Rafinesque preoccu- 

 pied the name Ceratops I have suggested that the term Proceratops be used in its stead. (See Am. Jour. Sci., 4th ser., vol. 21, p. 144.)— R. S. L. 



