152 THE CERATOPSIA. 



The squamosals are very long and slender and are united with the parietals only by an 

 open suture. At their anterior extremities the squamosals are firmly coossified with the post- 

 frontals and the jugals. The inferior and anterior angle of the squamosal is not so much produced 

 as in Triceratops, and the quadratojugal notch is not so deep. The squamosal is more expanded 

 in front of the groove for the quadrate in the present genus than in Triceratops. The transverse 

 diameters of the quadrate at or in front of the groove for the quadrate and just behind the 

 quadratojugal notch are subequal in the present genus. 



The frontal region is broad and the supraorbital horn cores are well separated at their 

 bases; they are much compressed, ovate in cross section, with apex of oval directed anteriorly. 

 The horn cores are directed upward, outward, and forward. 



The orbits are elliptical in outline, with the longer diameter nearly horizontal and not nearly 

 so vertical as in those species of Triceratops which have elliptically shaped orbits. The orbits 

 in the present genus occupy a rather more anterior position than in the genus just mentioned. 

 The sutures are so completely closed in this region that it is impossible to determine the extent 

 to which the various elements enter into the construction of the orbit. The lachrymals, pre- 

 frontals, and frontals are so fused with one another and with the postfrontals that their outlines 

 can not be distinguished. A very large round foramen pierces the prefrontal on the right side 

 just within the strong orbital border. There is no corresponding foramen on the left side, and 

 the presence of this foramen of the right side is therefore probably of pathologic origin and of 

 no specific importance. 



Beneath the orbits the jugals are much expanded and the external surface of the skull in 

 this region slopes downward and outward and is much less nearly vertical than in the genus 

 Triceratops , making the skull appear extremely broad when seen from above. In front of the 

 orbits the facial region contracts very abruptly and appears short and much compressed when 

 seen from above, with a short nasal horn core, broad at the base and sharp above and directed 

 upward and forward. The nasals are completely fused with one another and with the adjoining 

 elements. There is a large lachrymal foramen, situated well in advance of the orbit, but 

 owing to the age of the individual it is impossible to tell whether it is situated entirely within 

 the maxillary, as in Triceratops (Sterrholophus) fiahellatus, or between that bone and the nasal, 

 as in Triceratops prorsus. The superior surface of the skull in front of the paired supraorbital 

 horns presents a gently concave fore-and-aft surface, while behind these horn cores the post- 

 frontals fall away rather abruptly to meet the parietals and squamosals. 



Principal measurements of the type. 



Mm. 



Distance from posterior border of orbit to extremity of squamosal 1, 640 



Distance from anterior border of orbit to front of nasal horn core 440 



Expanse of jugalg 810 



Greatest length of skull (estimated) 2, 200 



Fore-and-aft diameter of supraorbital horn core at base 266 



Transverse diameter of supraorbital horn core at base 153 



Transverse diameter- of supraorbital horn core 6 inches above base 175 



Fore-and-aft diameter of supraorbital horn core 6 inches above, base '. 108 



Circumference of supraorbital horn core 6 inches above base 490 



Circumference of supraorbital horn core at base 638 



Height of nasal horn above inferior border of nasals 148 



Transverse diameter of nasals at base of nasal horn core 90 



Distance between orbits 432 



Antero-posterior diameter of orbit 166 



Vertical diameter of orbit 119 



Torosaurus gladius Marsh. 1896. 



Type (No. 1831, Yale Museum), from the Laramie of Converse County, Wyo. 



Original description in Am. Jour. Sci., 3d ser., vol. 42, Sept., 1891, pp. 266-267. 

 Marsh, O. C, Am. Jour. Sci., 3d ser., vol. 43, p. 84; Sixteenth Ann. Rept. U. S. Geol. Survey, 1896, pt. 1, p. 215. 

 Dana, J. D., Manual of Geology, 1895, p. 846. 

 Lambe, L. M., Contr. Canadian Pal., vol. 3 (quarto), pt. 2, p. 66. 

 Osborn, H. F., Contr. Canadian Pal., vol. 3 (quarto), p. 15. 



