THE SIGNIFICANCE OF HUMAN ANOMALIES, 725 



there are more, and, when this occurs, the extra ribs are carried by 

 the neck (cerrical) or loin (lumbar) vertebrae. I have specimens in 

 my collection of both varieties, cervical and lumbar (see Fig. 2, C), 

 These supernumerary ribs do not occur very frequently ; still, every 

 anatomist has observed them. Their occurrence becomes more intel- 

 ligible when we know that in crocodiles, birds, and the three-toed 

 sloth, neck or cervical ribs exist normally ; that in crocodiles, alligators, 

 and some other animals, loin or lumbar ribs are never absent ; and that 

 in man traces of them exist in the muscles of the abdomen. In the 

 human embryo, in an early stage, a rib is always seen connected with 

 the seventh neck- vertebra, but before the fifth year of life it becomes 

 blended with the ordinary transverse process (Fig. 2, T) ; occasionally, 

 however, this rudiment goes on developing, till it becomes a more or 

 less perfect cervical rib (see Fig. 2, G). 



SuPRA-coNDYLOiD Pbocess. — It is not uncommon to find, in the 

 humerus or arm-bone of man, a hook-like process on the inner side of 

 the lower end, having a downward direction; this, with a band of liga- 

 ment which connects its tip with the humerus lower down, forms a 

 foramen or opening through which pass the great artery and nerve of 

 the arm (see Fig. 3, A, £). This foramen is found in about three per 



Pig. 3— a, the supracondyloM process of the human Pig. 4.— Bonbs of Fore-mmb of Cat. S, 

 humerus ; B, the ligament which completes the fora- the supracondyloid foramen, with ves- 

 men. (After Struthers.) Bel and nerve passing through. (After 



Struthers.) 



cent of recent skeletons, but much more commonly in the skeletons of 

 ancient races. In very many bodies a trace of this foramen is seen, 

 represented by a very small bony prominence, or only by a band of 



