Cope.] o [April 17, 



vided, and the notochordal canal is small. The caudal vertebra have a 

 groove, more or less obliterated by coosification, surrounding the middle 

 of the centrum, and cutting off a part of the base of the neural spine above. 

 This looks as though the genus possesses intercentra, which were primi- 

 tively separated by the protovertebral fissure. The posterior part of the cen- 

 trum carries chevron bones, which are distinct from it. Besides the zyga- 

 pophyses, there is, in the dorsal vertebrae, a modified form of zygosphen, 

 though there is no zygantrum. The former consists of a roof-like projec- 

 tion of the neural arch above each prezygapophysis, which is applied to the 

 superior surface of the postzygapophyses. In some of the vertebrae, this 

 zygosphenal roof is horizontal ; in others it is slightly oblique, rising out- 

 wards on each side, in the manner of a true zygosphen. It differs further 

 from a true zygosphen in being fissured vertically, above the neural arch, 

 but there is no corresponding process of the adjacent vertebra to occupy 

 it. On the contrary there is a corresponding fossa of the posterior side of 

 the vertebra in front. These fossae may be points of insertion of ligaments 

 which strengthen an articulation otherwise weak. 



The ribs appear to be coossified with the centra, so that it is difficult to 

 say whether they are truly ribs or diapophyses. In one specimen, the 

 proximal ends of the ribs are seen to be expanded, and applied to the cen- 

 trum so as to embrace it. These expanded extremities are simple and are 

 separated on the median line of the centrum by a narrow space. Others are 

 not so expanded proximally, but contract to their connection with the cen- 

 trum. In some of the centra each side is produced into a depressed coni- 

 cal apex in the position of a diapophysis. The position of these vertebrae 

 is uncertain. The ribs are long, cylindric, curved and remarkably robust, 

 having characters like those of the genus Ischyrosaurus of the Laramie 

 formation, or of Mesosaurus of Gervais. They could not have had any 

 movement on the vertebrae. 



The scapular arch is represented by a coracoid bone, which though isola- 

 ted, is lying on a slab with numerous remains of this genus. As no other 

 form is represented on the slab, I suppose the coracoid to belong to Stereo- 

 sternum. It is expanded fore and aft, most so posteriorly, and possesses a 

 supracoracoid foramen. Its internal border presents a deep notch oppo- 

 site the glenoid cavity. 



Portions of several humeri are preserved. They demonstrate either that 

 the head is subround, or that if expanded it is at right angles to the distal 

 end. The latter is perforated near one of its borders by an epicondylar 

 foramen, but whether entepicondylar or ectepicondylar, I cannot ascer- 

 tain. The opposite foramen is represented by a shallow groove at the dis- 

 tal end of the opposite side. There are no well marked condyles of the 

 humerus. 



The head of the femur is truncate and subround, and without trochan- 

 ter. The shaft is subround and is of considerable length. There are no 

 distinct condyles, but the articular surface is convex anteroposteriorly. 

 The tibia is a stouter bone than the fibula, and its distal extremity is ex- 



