866 



TABLE V. — Relative weights of the body (P), the muscuius pectoralis major 

 {Mp) and the muscuius coracobrachialis (Mc), and relative surfaces of 

 the body (5) and the area of the wings (A) in 10 pairs, formed from 

 20 species of Birds. (Calculated from the determinations of A. Magnan) 



seems also required to keep I lie body, wliicli becomes disproportio- 

 nall}- lieaviei' with regard to ils surface, Moating. 



Tims through this research (he necessary certainty has been ob- 

 tained that between homoneuric species, under for the rest equal 

 circumstances, the weight of the muscles varies proportionally with 

 the body weight. If this holds between large and small homo- 

 neuric species, it may be assumed a fortiori that the individuals 

 of a same species and of equal, generally also of different sexes, 

 certainly possess no greater relative muscle weight than the smaller 

 individuals, because between them the brain weight, in function of 

 the body weigi)t, varies much less (han between homoneuric species. 



Kor man, however, in comparison with woman, the absolute 

 average weights of the muscles increase as the square of their average 

 body weights. Together wiih this also the brain weight, in function 

 of the body weight, as the square of tlie increase of the brain weight, 

 in function of the body weight, between individuals of identical 

 species, mostly even of different sexes. P^or man, compared with 



