1895.] The Significance of Anomalies. 131 
is it has been grossly disregarded, not only by popular scien- 
tists, but by some from whom better might be expected. To 
point out the animal in which a certain anomaly is normal 
has been too often offered as an explanation. Critical study 
makes many difficulties apparent. These are vastly increased 
when we consider that a satisfactory explanation must account 
not only for certain anomalies, but for all. At the very least 
there must be no case clearly at variance with the explanation. 
All anomalies have not the same significance. Certain ones 
represent structures widespread throughout mammals, some of 
them even in other classes of vertebrates. Three of these may 
be mentioned: the supra-condyloid process, the third trochan- 
ter, the para-mastoid process. Of the first there is usually no 
trace in man. The second is represented at most by a rough- 
ness of doubtful interpretation, in my opinion it is usually 
wholly absent. The third is wanting, or a mere point. The 
occurrence in man of a third trochanter is very common, that 
of the supra-condyloid process uncommon and a really large 
para-mastoid process is a great rarity. None of them occur 
normally in the Simiidee (the anthropoid apes). Of these 
structures the most general is the supra-condyloid foramen. 
In the primates it is practically universal among the Lemu- 
roide, but among the Anthropoide it occurs only among 
some of the smaller monkeys,—some of the Cebide. 
The third trochanter also is almost universal among the 
Lemuroids as a rudiment, and in some species reaches a mod- 
erate development. There are traces of it in some of the 
smaller monkeys, and it is occasionally seen in the gibbons 
and the chimpanzee. I have tried to maintain that the true 
third trochanter in man, occurring very often on delicate 
bones, is different from the rough line for the insertion of the 
gluteus maximus. 
The para-mastoid process is, if I am not much mistaken, 
rudimentary or wanting throughout the primates. 
When therefore, we find a supra-condyloid process which 
with the completing ligament, represents the supra-condyloid 
foramen, to account for it atavistically the shortest leap is to 
Journal of Anat. and Phys. Vol, XXIV. 
