226 Supracondvloid Foramen and Processes in Man 



taiix's observations prove, however, that the position of the usual process 

 is not fixed. Is it possible that it may wander so far as to appear over 

 the external condyle? 



The external supracondyloid process rests, so far as I know, on the 

 solitary observation of Barkow (13). It is not surprising that though the 

 reference to Barkow's paper is common enough, few seem to have any 

 definite idea of what he described, as his observations are not easily 

 accessible. Having had the advantage of seeing the original, which is 

 in the Surgeon-General's Library at Washington, I give a photograph 

 (Fig. 3) of his figure so that others may judge for themselves of this 

 process. Gruber (14) is very severe in his criticisms of Barkow. The pro- 

 cess, he says, is neither in the place it should occupy were it the ana- 

 logue of the process in mammals it is held to represent ; it is in no rela- 

 tion to the radial (musculo-spiral) nerve; it points downwards instead 

 of uj)wards. I am not quite convinced that it is impossible that the 

 nerve should pass under this process, though it certainly is placed below 

 the usual course of the nerve. It is probable that it is a mere irregular 

 ossification of the external supracondyloid fibrous tissue; but after all 

 it has a decided resemblance to the internal supracondyloid process. I 

 believe that it is of no significance. 



In conclusion I would say something as to the explanation of the 

 occasional appearance of the supracondyloid process or foramen in man, 

 much discussed as this question has been. I had the honor of reading 

 a paper on the " Significance of Anomalies " before the Association of 

 American Anatomists in 1894 (15). One of the instances I chose was the 

 supracondyloid process. While I could offer no satisfactory explana- 

 tion, it seems to me that I showed well-nigh insuperable objections to 

 the common plan of calling them reversions. I then said, " It is clear 

 that if an anomaly in man is to be called a reversion, either the species 

 in which it is normal must have been in the direct line of ancestry, or 

 there must have been a common progenitor." I am inclined now to add 

 that it is reasonable to expect that this common progenitor should be, 

 as one may say, somewhere within call. I also laid stress on the argu- 

 ment that similarity of structure does not necessarily imply common 

 descent; and this is true when we consider the normal structure of ani- 

 mals of different orders, or even I may say of different classes, as well 

 as the variations. 'Very valuable work has been done by distinguished 

 colleagues since then. Professor Huntington (16) has emphasized the 

 occurrence of such phenomena and has stated the matter with great 

 clearness. Treating of muscular variations he distinguishes three kinds. 

 Archeal reversional variations repeat conditions which are not found in 



