580 BULLETIN UNITED STATES GEOLOGICAL SURVEY. 



and included concavity are pronounced from near the beginning of the 

 caudal series. 



The surfaces of the vertebral centra differ somewhat in different por- 

 tions of the column. In the cervicals, it is lined with obscure ridges, 

 which become more prominent as they approach the articular faces. 

 Here they break up into series of small irregular tubercles. On the 

 posterior cervicals, the ridges are most prominent in the inferolateral 

 region. The corresponding surfaces in the dorsal vertebrae are smooth. 

 In the caudals, the rugosities reappear, and have on the general sur- 

 face a reticulate character. This is pronounced on the distal caudals, 

 so that thej^ are almost pitted in places. 



A number of ribs are preserved, some of them nearly in place, and 

 imbedded in the matrix. They are robust, and the heads are expanded 

 to the articular faces. The shaft at and below the curve is in section a 

 triangle with rounded angles. Those attached to the twenty-fifth, 

 twenty-sixth, and twenty-seventh dorsal vertebras are straight and 

 short, at least their distal extremities appear in the present state of the 

 specimen to be unbroken. They are the forerunners of the free caudal 

 diapophyses, which they^ exceed in length. 



The limbs, which have not been previously seen in this genus, are 

 characterized by the shortness of the proximal and medial elements, as 

 compared with the length of the manus and pes. The anterior limbs are 

 a little the larger. The humerus is very robust; its shaft is subcylin- 

 dric, and the distal extremity is greatl}^ expanded, so that the width is 

 but little less than the length. The proximal end of the shaft turns in- 

 ward to the oblique head ; the external face of the shaft continues in a 

 plane without curvature, which terminates in a broadly truncate tuber- 

 osity with prominent lateral angles. The surface then contracts from 

 this trochanter, and forms the short inwardly-directed neck. The ulna 

 is a flat bone broader than long, of a subquadrate outline, with the in- 

 ner border deepl^^ concave. The radius is a little smaller, broader than 

 long, and six-sided. The proximal and ulnar sides are longest, and the 

 latter is moderately concave. The ulnar carpal is the largest, and is 

 subquadrate in form. The intermedium is large and suboval; its 

 contact with the radius is greater than with the ulna. The radiale is 

 subround and quite small ; it is in contact with the external distal facet 

 of the radius, and is separated from the intermedium by the first phalan- 

 geal carpal, which is adjacent to the median distal facet of the radius. 

 There are four of the phalangeal carpals, or those of the second series, 

 of which the first, or external, is in line with those of the first series. It 

 is followed by a metacarpal, which is in the second transverse series of 

 the carpals. The two external carpals of the first series each support a 

 corresponding one of the second series ; the third in the same line above 

 described is followed by two bones, the third of the second series and 

 the first metacarpal. Of the second series, the fourth and third are sub- 

 rouud and a little broader than long; the second is longer than broad, 



