MONOCLONIUS CRASSUS. 



77 



and general characters they agree well with what we might expect to obtain in M. crassus, 

 and some of them may pertain to the same skeleton as the type. The centra of all are short, 

 somewhat constricted medially, with nearly plane or slightly biconcave extremities. The 

 neural arches are of moderate height and somewhat constricted just above the neural canal , 

 which is of only moderate di- 

 mensions. The neural spines y~~\ 

 are of moderate length and 

 compressed. The transverse 

 processes are triangular in 

 cross section. There is a 

 tubercular rib facet at the 

 extremity of each transverse 

 process and a capitular facet 

 situated on the side of the 

 centrum in the anterior dor- 

 sals, on the neural arch in 

 the median dorsals, and on 

 the inferior side of the trans- 

 verse processes in the poste- 

 rior dorsals. 



The anterior and poste- 

 rior zygapophyses of oppo- 

 site sides are distinct, though 

 not widely separated in the 

 vertebrae of the anterior and middorsal regions. In the posterior dorsals, however, they 

 are confluent. 



The caudals. — In the collection there is a single caudal, which, though not the first of the 

 series, I refer to the anterior caudals. It is biconcave, with a small transverse process 



springing from near the middle of the 

 side of the centrum. The centrum is 

 short and constricted medially below the 

 transverse processes. The neural arch is 

 low and the zygapophyses of opposite 

 sides well separated. The. spine is want- 

 ing in the present specimen. 



The pelvis. — In his original description 



Fig. 79. — A, Anterior view of posterior median dorsal of type of Monoclonius crassus Cope, No. 

 3998, American Museum of Natural History; B. side view of same, c, Capitular rib facet; 

 az, anterior zygapophysis; pz, posterior zygapophj'sis. Both one-fourth natural size. 



Fig. 80. — A, Anterior view of anterior dorsal of type of Monoclonius crassus 

 Cope, No. 3998, American Museum of Natural History; B, side view of 

 same, az, Anterior zygapophysis; pz, posterior zygapophysis; c, capit- 

 ular rib facet. Both figures one-fourth natural size. 



Fig. 81.— A, Anterior view of an anterior caudal of type 

 of Monoclonius crassus Cope, No. 3998, American Mu- 

 seum of Natural History; B, side view of same, az, 

 Anterior zygapophysis; pz, posterior zygapophysis. 

 Both figures one-fourth natural size. 



of the genus and species Cope simply mentions the ilium as being elongate. There are in the 

 collections from the Judith River beds two ilia. The larger of these is nearly complete, and 

 although a little small in comparison with the sacrum described above, it corresponds very 

 well in character and state of preservation with the parietals; hence I have referred it to 



