TOEOSAUEUS GLADIUS. 153 



The type (No. 1831, Yale Museum) of the present species was found at the locality 

 marked +19 A, PL LI. The horizon was considerably lower than that which afforded the 

 type of the preceding species. The fragmentary remains upon which it was based J>y Professor 

 Marsh were found in a thick bed of shale which forms the gentle northern slope of the low 

 divide between Lightning and Cow creeks, midway between and at a distance of about 1 mile 

 from, the mouths of those creeks. 



Professor Marsh's description of the species was as follows: 



A second species of apparently the same genus is represented by various portions of a skull in good preservation. In 



this specimen the nasal horn core is short and obtuse, and nearly upright. The main horn cores are elongate, oval in 



outline, and in position resemble those of the skull above described. The most remarkable features in the present specimen 



are the squamosal bones, which are greatly elongated and so attenuated as to have the general shape of the blade of a sword, 



thus suggesting the specific name. These bones, moreover, show but slight evidence at their distal extremity of union with the 



parietals. As the inner margin is rounded for nearly half the length, this feature will distinguish the present species from 



all others hitherto described. 



The following are some dimensions of portions of this specimen: 



Inches. 



Length of horn core from top of orbit to summit 27 



Antero-postcrior diameter of same horn core at base 8 



Transverse diameter of same '. 5 



Length of squamosal behind exoccipital groove 55 



Greatest width 15 



Width at middle 9 



These interesting specimens were also found in the Laramie of Wyoming by Mr. J. B. Hatcher. 



The type of the present species consists of a nearly complete parietal, left squamosal, a 

 supraorbital and nasal horn core, an epijugal, the occipital condyle, and other skull fragments 

 of less importance. 



The type of the present species represents the extreme development of the form of parietal 

 crest that is peculiar to this genus. The squamosals, as shown in fig. 14, are extremely narrow 

 and elongate. The parietals are very broad and long and are interrupted by a pair of huge 

 supraorbital fontanelles, well shown in fig. 12. The posterior border of the parietals was 

 emarginate at the median line. The median bar of the parietals was broad, thin, and smooth, 

 especially at the posterior extremity. Its superior surface is nearly flat at the posterior extremity, 

 but becomes more convex anteriorly, where it presents three low, rugose prominences arranged 

 in a longitudinal series. In front of and posterior to the supratemporal fontanelles the parietals 

 expand into broad, thin plates, which form respectively the anterior and posterior borders of 

 the fontanelles. Below, these plates are united by a thin bar of bone, which unfortunately is 

 not complete in the present specimen, but which, when in position, overlapped the superior 

 border of the squamosal and formed the inferior lateral margin of the large fontanelle. There 

 were no epoccipital bones on the posterior border of the parietals such as are present in other 

 genera of the Ceratopsia, but the sharp, thin posterior border of these elements presents on 

 either side of the median line a series of nine elongated prominences alternating with eight 

 shallow emarginations, which give to the periphery of these bones the same peculiar scalloped 

 effect that in Triceratops is produced by the epoccipitals. 



The narrow and elongate squamosals for 25 centimeters at their posterior extremities 

 present a rather thick concave inner lateral border, against and into which fits the posterior 

 external lateral border of the parietal. In advance of this for a distance of nearly a meter the 

 external margin of the parietal overlaps the internal margin of the squamosal. This over- 

 lapping and underlapping is carried to the greatest extent in the region opposite the middle 

 of the supratemporal fontanelles, where it amounts to as much as 6 centimeters. Anteriorly 

 the inner borders of the squamosals are much thickened and the inferior surface of each is 

 produced into a long, narrow plate which becomes wider anteriorly. This plate passes beneath 

 the margin of the anterior plate of the parietal and forms a part of the floor of the large supra- 

 temporal fossa, while the thickened superior marginal border of the squamosal in this region 

 forms the external lateral boundary of this fossa. The postero-external lateral border of the 

 squamosal is without either sinuosities or epoccipitals, but anteriorly this border is marked 

 by a series of four gentle prominences separated by three elongate and shallow emarginations. 



