MEMOIRS OF THE UNIVERSITY OF CALIFORNIA. 



expanded, one being nearly round and apparently deeply hollowed terminally. 

 The other end is broadened and is considerably flattened in a plane standing 

 almost at right angles to a less pronounced plane of compression of the oppo- 

 site termination. These elements may represent caudal ribs from a region 

 somewhat farther back in the series than the location of the more elongated 

 and evenly rounded ribs described above. The less compressed end of the 

 shorter bones corresponds quite closely with the proximal termination of the 

 certainly known ribs described above, and is also somewhat smaller than the 

 heads of these ribs. The flattened and expanded end may represent a modi- 

 fication in the terminal portion of a sacral rib, or may be the normal form in 

 all anterior caudal ribs. 



With the vertebrae and ribs of this specimen (10620) there are two ele- 

 ments, one of which (pi. 13, fig. 2) represents either a propodial or an anterior 

 epipodial element of the posterior limb; the other (pi. 13, fig. 3) is either a 

 posterior epipodial element of the hind limb or the ischial element of the 

 pelvic arch. The first mentioned bone is much less elongated than either the 

 femur or the tibia of Cymbospondylus pctrinus, and is most nearly comparable 

 with the tibia of Shastasaurus or Delphi nosaurus. As there is no trace of a 

 proximal trochanteric elevation, though the bone is perfectly preserved, it may, 

 presumabl} 7 , be considered as the preaxial, epipodial element, but of a type 

 quite different from that seen in C. petrinus. 



The other bone has almost the same axial diameter as the element referred 



to as the tibia, but is considerably thinner, particularly 

 at the distal end. This element is slightly constricted 

 medially, and greatly expanded distally. The distal 

 expansion resembles the broadening of the distal end 

 of the fibula in C. petrinus. If this element is the fib- 

 ula, the limb must have been much broader than in C. 

 pctrinus, and the epipodial region relatively shorter. 

 In any case the limb must have differed quite consid- 

 erably from that of C. petrinus, and suggests a special- 

 ization of the epipodial region approaching that of 

 Shastasaurus. 



Another specimen (no. 10821) from New Pass, con- 

 sisting of an isolated vertebral centrum (fig. 138) with 

 a portion of the neural arch attached to it, represents 

 the anterior or middle dorsal region. The centrum is 

 relatively elongated compared with those of the same 

 region in Shastasaurus, but does not differ greatly in 

 this respect from the corresponding centra of C. pc- 

 Irinus. The anterior and posterior faces are deeply ex- 



?. 138. Cymbospondylitx IK - 

 I'adanus, n. sp. ( ?) Lateral 

 view of anterior dorsal ver- 

 tebra, X V->. 



