C) HULKE, FOSSIL VEHTEBKATK REMAlNS FUO^f SPITZBEKOEN. 



concave in a horizoutal direction. This surface, from above 

 downwards to iiear tlic lowcr l)ordci- ol" tlie centrum, is almost 

 planc. 



Dimensions ol" series (2. d.): 



Aiitero-postei'ioi' Yertieal Horizoutal transverse 



diameter. diameter. diameter. 



0,3 Inch. 1 Inch. nearly. 0,0 Inch. 



Besides these there are several eaudal centra and impres- 

 sions, in two shale-slabs (2. b.), (2. c). They probably be- 

 louged to a ratlier larger individual and occupied a place in 

 the spinal columu intermediate between the two series ol" 

 caudals just described. All these centra have the same re- 

 markably oblong outline (the vertical diameter of the best 

 preserved centrum is 1,3 inch, whilst its horizontal-transverse 

 diameter is rather less than 0,6 inch.), their articular surfaces 

 exhibit the same striking ilatness and small deep pit nearly 

 at their middle. In some centra these surfaces are slightly 

 sinuous being nearly plane vertically and gently concave 

 horizontally. 



Their form and their proportions differ so much from 

 those which we have been wont to regard as typical of the 

 genus Ichthyosaurus, that but for their intimate association 

 with the \mmistakable paddle bones, and the link which these 

 constitute with the typical thoracic vertebra^, one raight have 

 hesitated in assigning these caudals to au Ichthyosaur, but the 

 evidence before me is, I think, conclusive in this matter. 



1 propose to distinguish this species by the nanie of its 

 discoverer, Prof. Nordenskiöld. In the great excess of their 

 vertical diameter the eaudal vertebrre resemble one found by 

 Captain, now Vice-Ad:ral Sir Ed. Belcher K. C. B., on Exmouth 

 Island in lat. 77° W N., long. 96° W. in 1852, and figured 

 in the appendix (p. o89) to his »Last of the Arctic \'oyages)), 

 by Prof. OwEN. My eudeavour, courtcously aided by Sir Ed. 

 Belcher and Prof. Owen, to trace this fossil for comparison 

 with the Spitzbergen Ones bas not been successful. Two 

 other discoveries of Ichthyosaurian remains witliin the arctic 

 circle have been recorded. An Ichthyosaurian vertebra was 

 found by Captain, now Sir Leopold Mc. Clintock, 14 ]\Iay 1853, 

 at Cape Wilkie, Lat. 7(5^ 20 N., Long. 117 20' W., the S. 



