PENTACERATOPS FENF.STRATUS 113 



remains, and was well preserved. In no place, according to Wiman, did it need any reconstruction. 

 Wiman's interpretation of the vertebral formula gives 20 presacrals — 9 cervicals and 1 1 dorsals. 

 There are also 1 1 sacrals and 28 caudals, the tail being incomplete. The standard ceratopsian 

 formula gives 21 presacrals. But the apparent discrepancy here lies in the fact that the 21st presacral 

 thoroughly coossiticd by its centrum and spine that it appears to be an integral part of the 

 sacrum, and has been so interpreted by Wiman. He believes that the tail was probably shorter 

 than in Monoclonius {Centrosaurus), for the last of the preserved vertebrae are so small that only a 

 few can be lacking. This is another point of agreement with Anchiceratofs in which the number of 

 caudals is 38 as compared with 46 for Monoclonius (Centrosaurus). The entire skeleton is robust, 

 compared with the Belly River forms, but not more so, relatively, than in Anchiceratofs. The 

 highest point in the vertebral column lies over presacral XIV, whereas on vertebra X the dia- 

 pophysis rises higher than in any preceding vertebra, although this is foreshadowed to a much less 

 extent in IX. The tenth is the first one on which the capitular rib facet rises from the centrum to 

 the neural arch and is therefore the first thoracic according to Williston, Brown, and Wiman. 



The sacrum, as now constituted in this old animal, contains 1 1 vertebrae, as the centrum of the 

 last presacral is fully fused with that of the succeeding vertebra. The first parapophysis arises from 

 the second and third actual sacrals, but does not sweep aft to the extent seen either in Monoclonius 

 (Centrosaurus) or Triceratops. Apparently, five parapophyses fuse to form the acetabular bar 

 which abuts against the ilium, rather than four as in Monoclonius (Centrosaurus) and Triceratops. 

 Otherwise, the sacrum is not unusual. The ilia are quite similar to those of Monoclonius (Centro- 

 saurus), as seen from below, except that posteriorly they extend further aft. The ilium is quite 

 Triceratops-Yike except that the pubic peduncle is relatively smaller in Pentaceratops. The pubis is 

 comparable to that of Monoclonius (Centrosaurus) except for its greater robustness, but the ischium 

 differs markedly in its degree of curvature, which is greater than that of any other known ceratop- 

 sian, even Triceratops. The shoulder girdle is also very robust but otherwise quite typical. As 

 posed by Wiman, the distal end of the scapula reaches to within three vertebrae of the anterior end 

 of the pubis (pseudopectineal process), making a very closely coupled animal. 



There is nothing distinctive about the fore limbs. The femora, on the other hand, are peculiar. 

 Wiman says they are somewhat deformed in that they are compressed from anterior to posterior. 

 This may be so, although a certain fore and aft compression is not unusual with the Ceratopsia. 

 The remarkable feature, however, is their curvature when viewed from either front or rear. This 

 is much more marked than in any ceratopsian I have seen, and must have bowed the thighs outward 

 in an extraordinary manner. The distal face of the combined tibia and astragalus is also peculiar in 

 that it is not perpendicular to the long axis of the bone but looks inward as well as downward, 

 departing from the horizontal by about 20°. The fourth trochanter of the femur is more prominent 

 than usual. Whether this bow-legged condition was generic or an individual departure from the 

 normal cannot be determined from this one specimen. It is certainly unique among all of the 

 ceratopsian skeletons which are known to us. The proportionate lengths of the several limb bones 

 are comparable to those of Chasmosaurus and Monoclonius (Centrosaurus) nasicornus. Foot bones 

 are present, but Wiman has not attempted to identify them as they were confused in the quarry. 



Dimensions of Skull A 

 (After Wiman) 



Length, from rostrum to highest point of crest 2160 mm. 



Height of left supraorbital horn 600 



Circumference of same at upper edge of orbit 500 



Height of right supraorbital horn 580 



Circumference of same at upper edge of orbit 520 



Height of nasal horn 220 



Circumference of same at base 250 



Length of epijugal horn core 100 



Circumference of same at base, left 290 



Circumference of same at base, right 230 



