1893.1 119 [Dwight. 



EIGHT. 



Female Present 33 



Wanting 75 



Total 108 



Per cent, present 30.5 



Both Sexes Present 122 



Wanting 177 



Total 299 



Per cent, present 40.8 



The next table shows the results of observations on both sides of two 

 hundred and fifty subjects. 



Psoas Pakvus. Records op Both Sides op 250 Subjects, 165 Male, 



85 Female. 



male. female. both sexes. 



Present on both sides 60 = 36.3% 20 = 23.5% 80 = 32% 



Present on neither side 84 = 50.9 53=: 63.3 137 = 54.8 



Present on right side -i -i ■! 



""''^y 14 21 = 12.7 ^ ^12 = 14.1 19 ,'33 = 13.2 



Present on left side j 



only 7 '' 7 '' 14 ■^ 



Total 165 = 99.9 85=99.9 250=100.0 



This shows the muscle decidedly less frequent than Gruber found it, 

 and a little more frequent than would appear from the English observa- 

 tions ; thus suggesting the influence of race. 



In order to study the relative variability of muscles, to ascertain whether 

 the presence of one occasional muscle renders the presence of another 

 more probable, the pyramidalis was chosen as a starting point. It was 

 chosen because it is generally held that while it is present in a large 

 majority of instances it is not uncommonly wanting. Though this im- 

 pression is, I believe, general, there is, so far as I know, no large series of 

 observations on the pyramidalis excepting Hallet's. In his two hundred 

 subjects he found it wanting in the proportion of once in nine or ten.* In 

 the following table of observations at the Harvard Medical School, indi- 

 vidual sides only are considered. 



Pyramidalis in 673 Sides. 



EIGHT. 



Male Present 180 



Wanting 45 



Total 225 



Per cent, present 80 



* Loc. cit. It is worthy of notice that in his first hundred it was wanting once in every 

 three subjects, and once in every fifteen in his second hundred. 



