32 



4) The fact that the lower type of joint is found three times as 

 often on the left side as the right — 9:3. 



As I have before said I am not prepared at all events at present 

 to account for the evident bias toward the right side! If one fall back 

 upon the theory that it may be connected with "right-handedness" I am 

 bound to confess that I cannot see clearly that this explains the 

 matter; certainly the 6 th costal cartilage is the lowest point of 

 attachment of the pectoralis major muscle, but I do not know that 

 the right great pectoral muscle is much more developed than the 

 left, at all events those fibres of it which arise from the 6 th costal 

 cartilage. 



From the following table in which both sides are compared some 

 idea will be gained as to the conditions existing in the 50 specimens 

 examined. 



Total number examined 50 Total 50 



Number of schizarthroses 33 16 



Number of fibroses 3 9 



Number of times joint is absent on both sides 11 



In conclusion I should like to say that the number of cases in 

 which joints were absent on both sides is higher than it otherwise 

 would have been, because in four of the cases examined there were 

 8 costal cartilages articulating on both sides of the sternum, and in 

 those cases the 6 th and 7 th cartilages played the same part with 

 reference to the formation of a joint as the 5 th and 6 th did in the 

 majority of cases, i. e. in all the cases the 6 th articulated with the 

 7 th on the right side but not on the left. I do not know what the 

 origin of the pectoralis major muscle was in these cases. 



