1911] 



Merriam: Saurian Fauna of Spitzbergen. 



321 



the Italian specimens thus far described in possessing a sixth 

 digit. The first three segments of the anterior limbs are prac- 

 tically identical with those of Cymbospondylus(l) natans, a 

 Mixosaurus-like species from the Middle Triassic of Nevada. The 

 posterior limb (fig. 4) is almost identical in form with that of 

 Mixosaurus cornalianus, even to the duplication of a peculiar 

 arrangement of the proximal carpals found in the Italian species. 



Pig. 4. Mixosaurus (?) nordenskioldii (Hulke). Pelvic arch and pos- 

 terior limb, X %. P, pubis; I, ischium. (After Wiman.) 



The pelvic arch (fig. 4) is almost identical with that in most 

 specimens of the American Cymbospondylus, and differs from 

 that of Mixosaurus in the absence of an obturator foramen in 

 the pubis. 



The pectoral arch is like that of Mixosaurus excepting in the 

 form of the interclaviele, which has a remarkably wide trian- 

 gular form with a distinct reentrant angle on the anterior side. 



The complete vertebral column is not known, but fortunately 

 considerable numbers of vertebrae, including the posterior dorsal 

 region and a large part of the tail, were found in a continuous 

 series (fig. 5). As in Mixosaurus cornalianus, the tail makes a 

 gentle upward curve near the middle and droops slightly at the 

 posterior end. In the Spitzbergen form as represented in the 

 specimen figured by Wiman the upward curve is much nearer 

 the dorsal region than in M. cornalianus ; in contrast to Cymbos- 

 pondylus, in which the curve is farther back than in the Italian 

 species. 



