171 



three-quarters of an inch. There are, however, some fragments which 

 show that this species attains a much greater size, ]ierhaps more than 

 double the dimensions here given." 



"Form, and ]joc. — Occurs in the dai'k argilhiceuus, compact limestone 

 of Xanaimo River, Vancouver's Island. '"-Shuniard. 



Nunaimo Eiver, two miles and a quarter up, Protection and Saturna 

 Islands; Yesuvius Bay on Salt Spring or Admiralty Island ; in Division 

 A ; a few, not very good specimens from each of these localities. Sucia 

 Islands, also in Division A, ninety-tive examples, many of which are 

 well preserved and nearly ])erfect; J. Eichardson, 1871-75. 



In about ninety or ninety-tive per cent, of the specimens of /. Vancou- 

 verensis collected by Mr. Eichardson, the height of the shell is manifestly 

 greater than its length. The margin of the buccal side of this prevalent 

 form of the species, though broadly rounded in some individuals, is 

 straight or truncated almost verticall}' in others, and these latter shells 

 can scarcely be distinguished from the I. alius of Meek. I. ElUotii of 

 Gabb apj)cars also to be possibly synonymous with /. Vancoiwerensis. It is 

 quite likely that the present species may ])rove to be identical with the 7. 

 propinquus of Munster, M'hich Eichwald, Geinitz, Pictet and Stoliczka 

 regard as a large variety of I. problematicus, Schlotheim. Goldfuss' des- 

 cription and tigures of 1. propinquus ap])ly remarkably well to most 

 specimens of /. Vancouverensis, though, as a general rule, the concentric 

 plications of the latter shell are generally more prominent, distant and 

 regular than they are represented as being in I. propinquus. 



A few excejjtional specimens of I. Vancouverensis broaden rapidly 

 below the middle, so that the maximum length of the shsll equals, or 

 even exceeds the height. It was proljablj^ this form of species that Dr. 

 Shumard had in view when he comjiared it Avith T. convexus and I. 

 Sagensis. I. convexus, however, has a long hinge line, which is nearly 

 parallel with the longer diameter of the valves and belongs, therefore, to 

 the sub-genus Catillus : Zittel and Pictet both think it may be a variety 

 of J. Crippsi. I. Vancouverensis, on the other hand, always has a short 

 hinge line, and is a typical Inoceramus, in the sense in which that genus 

 has recently been restricted and redefined by Meek. 



Some specimens of the broad, short variety of /. Vancouverensis 

 approach rather near to 1. JS'ebrascensis, var. Sagensis, so far as the 

 general outline of the valves is concerned, but Mr. Meek says that the 

 beaks of the latter shell do not rise much above the hinge margin, and are 

 scarcely incurved, whereas those of I. Vancouverensis are both prominent 



