Cope.] ^>36 [D ec. 21, 



the glenoid and the coracoid, are well distinguished, and their surfaces are 

 like the corresponding faces of other bones, pitted coarsely. 



The coracoid bone is of proportionately small size. It is of an irregu- 

 larly quadrate form, with the proximal extremity the shortest. The ar- 

 ticular face is large, and is presented obliquely away from the long axis of 

 the plate. There are no emarginations nor intermediate processes, and the 

 perforating foramen is well removed from the border. 



Pelvic bones of two forms are present. Neither of them resembles pel- 

 vic bones of Dinosauria, and are least of all similar to the forms of ilium 

 which are known in that order. One of them is a robust L -shaped bone, 

 one limb of which is expanded into a wide fan-shaped plate ; and the other 

 is stouter and of sub-equal width, terminating in a stout sub -triangular ar- 

 ticular extremity. The face of this limb of the bone which looks away 

 from the fan-shaped plate is concave throughout its entire length, forming 

 a large part of the acetabulum. Both edges of this cavity are free and 

 rounded. The absence of articular faces above the acetabulum renders 

 the identification of the bone with either pubis or ischium difficult. The 

 second pelvic bone is larger than the first, and unlike it, is in one plane. 

 Its form is that of a low triangle with a long base, at each extremity of 

 which the angles are truncated. The "basal" border is gently concave in 

 the long direction and thick and convex in the cross -section, The two 

 "sides " of the triangle are rather thin margins, but one of them is thicker 

 than the other. One extremity of the bone is more robust than the other, 

 and is divided into two planes. The one is transverse and sub -triangular, 

 and applies to the extremity of the stout or acetabulum limb of the other 

 pelvic bone. The other is smaller, is oblique and concave, and when the. 

 two bones are placed in relation, forms a continuation of the acetabular 

 surface already described. Within this and the proximal portion is a large 

 foramen which resembles the pectineal perforation of the pubis. 



The femur is long and without prominent third trochanter, this process 

 being represented by a low ridge. The condyles have an extensive poste- 

 rior sweep, and are separated by a shallow trochlear groove in front. A 

 tibia which was found with the other bones, is much shorter than the for- 

 mer, and has a much expanded head. It is very robust, especially at the 

 distal extremity. The astragalus was evidently distinct from it. A meta- 

 podial bone is very robust. Its extremities are much expanded, and the 

 shaft contracted, and it is furnished with a prominent median keel on one 

 half of its posterior aspect. 



Several. genera have been described, which possess some of the features 

 presented by those to which the present animal belongs. The following 

 are characterized by the presence of the lateral sinuses of the vertebral 

 centra : Megadactylus Hitch., Cetiosaurns Owen, Omithopsis Seeley, 

 Bothrospondylus Ow., and Pneumatarthnis Cope. The first of these may 

 be dismissed with the remark that its caudal vertebrae possess the sinuses 

 as well as the dorsals, which we have seen is not the case with the Colo- 

 rado animal. The centra of Cetiosaurus according to Owen, and those of 



