1687.] PROCEEDINGS OF UNITED STATES NATIONAL MUSEUM. 9 



Viewed from Professor Allen's standpoiut these remarks have very 

 great weight, and I have hitherto been inclined to accept his decision 

 as hnal. During- my examination of Mr. E. W. IS'elson's Alaska collec- 

 tion, however, I was very much struck by the uniformity of relation of 

 parts presented by the skulls of the Canada lynx which he collected. In 

 all of his skulls, and, as I afterwards ascertained, in all of the skulls from 

 British America and the northern parts of the United States, in the 

 :N"ational collection, the portion of thepresphenoid visible upon the un- 

 der surface of the skull is flask-shaped, the convexity being forward. 

 Again, in all these skulls the anterior condyloid foramen is large, iuid 

 looks downward, and is not confluent with the foramen J acerum poster ius. 

 Comparing these skulls, which had been labeled L. canadensis, with 

 those marked L. riifus, fasciatus, and maculatus, I find that in the latter 

 the visible portion of the presphenoid is triangular or linear in outline, 

 and that the anterior condyloid foramen is confluent with the foramen 

 lacerum posterius. 



These characters are of minor importance, but their constancy makes 

 them valuable for the division of the genus. The shape of the exposed 

 portion of the presphenoid can scarcely have any physiological signifi- 

 cance, but the slight change in the position of the anterior condyloid 

 foramen may to some extent influence the direction of the hypoglossal 

 nerve. Further than this, these characters probably have no special 

 significance. They are simply differences in detail of structure, which, 

 having been established, are perpetuated from generation to generation. 



On account of their presence and constancy, however, I cannot, with 

 Professor Allen, regard the greater size and the differences of pelage ob- 

 servable in the Canada lynx as due entirely to climatic conditions. In 

 fact, in such skins of the Canada lynx as I have examined I find no 

 transition to L. rufus, such as binds the latter species with the so-called 

 L. maculatus and L.fasclatus. 



I do not regard the paleness of the fur in L. canadensis as a sign of obso- 

 lescence of marking, but as the normal style of coloration of a si)ecies 

 not highly colored. So far as the denseness of the pelage is concerned, 

 I am willing to believe that it is due entirely to climatic influences. The 

 color of the tail, however, I believe to be characteristic of the species. 



Of twenty-four skulls having the characteristics of L. canadensis in 

 the National collection, eighteen are from Alaska, two from the Red 

 River of the ]Siorth, and one from each of the following localities: The 

 main fork of Medicine Bow Creek, Liard River, Fort Simpson, and Ne- 

 braska. The sex of only four specimens is recorded; two of these are 

 males and two females. Forty-six other skulls, labeled L. rnfus, macula- 

 tus, and fasciatus, agree as regards the position of the anterior condyloid 

 foramen and the shape of the presphenoid. 



It is interesting to observe that two skulls from Sweden, labeled re- 

 spectively Felis lynx and Lynx cervaria, agree with L. canadensis in the 

 characters in question. I can only regret that I have no skulls of the 

 other nominal species of Eurasian lynxes at command for examination. 



