MKRKIAM: TRIASSTC If'ITTIIYOSAURlA. 140 



those teeth showed a simple oblong cross-section through the neek, the antero- 

 poslerior diameter being to the transverse as 2:1 or in some eases 2.5:1. A por- 

 tion of a crown protruding showed relatively coarse longitudinal fluting. 



In later examination by Dames (1895) of the specimens studied by Ilnlke, 

 the statements of Ifulke were substantiated, and attention was called to the 

 remarkable similarity of these specimens to Mixosaurus ? of the European Mid- 

 dle Trias. Dames noted several minor differences between the dentition of the 

 Spitsbergen form and that of 3f.(?) (damn. In -.(?) <tt<icnx the cross-sec- 

 tions of the teeth were stated by Dames to be nearly round, and the partitions 

 between the alveoli weak. In the Spitsbergen form the cross-sections are rela- 

 tively narrow transversely, and the partitions between the alveoli are strong. 

 According to the observations of the writer the most posterior teeth of -.(?) 

 (itin'KH may show some lateral compression. 



Taking oA T erything into consideration, the affinities of Hulke's /. norden- 

 xlsioldii seem closer with Gymbospondylus than with any other known genus. 

 The Spitsbergen form differs from Mixosaurus, particularly in the nature of 

 the rib articulation in the cervical or anterior dorsal vertebrae. 



In the great excess of their vertical diameter, the caudal vertebrae of C. (?) 

 iionh'iiNkioldii were stated by Hulke to resemble a vertebra found by Sir. Ed. 

 Belcher, in 1852, on Exmouth Island, lat. 77 16' N., long. 96 W. This specimen 

 was figured by Owen in the appendix (p. 389) to Belcher's "Last of the Arctic 

 Voyages. ' ' 



CYMBOSPONDYLUS (?) POLARIS (Hulke). 



Ichthyosaurus polaris Hnlke, Bihang K. Svenska Vet. Ak. Handlingar, Bd. 1, no. 9. 

 Ichthyosaurus (Mixosaurus) polaris (Damas), Sitzb. der Acad. der Wiss., Berlin, 1895, 



p. 1405. 

 Ichthyosaurus? (SJiastasaurusf) polaris (Merriam), Univ. Calif. Publ. Geol., vol. 3, 



pp. 87 and 88. 

 Shastasaurus polaris (Yakowlew), Verh. d. Kais. Russ. Min. Ges., Bd. 40, p. 194. 



This species was described by Hulke from fragmentary material obtained 

 by A. E. Nordenskiold in the Triassic of Spitsbergen. Yakowlew (1902, 1) 

 referred a vertebra to this form. Hulke studied two vertebral series. 

 One series included eight vertebrae, the other three. In the series of eight ver- 

 tebrae the outline of one of the centra is described as roughly that of a rather 

 narrow, long horseshoe. The dimensions of this centrum were as follows: 

 height, 3.9 in.; transverse diameter, 2.7 in.; anteroposterior diameter, 1.4 in. 

 About half way down on the side of one centrum was an oblong rib facet 1.2 

 in. long and .4 in. wide. The facet was slightly contracted at the middle and 

 extended obliquely downward toward the anterior border of the centrum. 



The anterior and posterior faces of the centrum were said to be deeply 



