THE DEVONIAN FOSSILS OF CANADA WEST. 357 
anterior extremity reduced to asmall auriculate expansion or obsolete. 
-The above figure shews the teeth and muscular impressions of /. 
Bayfieldii, Hudson River Group. 
VaNnuxeMIA Tomxkinst.-—(N. Sp). 
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Fig. 130. 
Fig. 129.— Vanuxemia Tomkinsi.—View of right side. 
Fig. 130.—View of anterior side. 
Description.—Ovate, exceedingly gibbous, cordiform; umbones 
very prominent ; beaks closely incurved. 
Placing the shell with the hinge-line in a horizontal position, we 
find that the line passing through the greatest length of the shell 
forms an angle with it (¢.e. with the hinge-line) of about 45°; the 
apical angle, or the angle formed by the slope in both directions from 
the umbones is about 80°; both of these slopes extend about half the 
length of the whole shell; from their extremities the remainder of 
the margin on the posterior, ventral and anterior sides is rounded, 
somewhat pointed in the middle. At the anterior extremity of the 
hinge-line there appears to be a small auriculate projection, but this 
point is not very well preserved in the specimen. 
Surface somewhat smooth, with obscure, concentric strie, three or 
four in the width of one line. Besides these there are some obscure, 
shallow, concentric, undulations of growth. 
The best preserved specimen is two inches and one-eighth in length 
—measuring from the umbones to the most projecting or pointed part 
