THE O.sTRACODA. 



275 



Table O. — Total specimens measured: 59 ? + 32 (J = 91. 



Kg. I. 



Ta-m. 



O* 



2-3 



22 



21 



2-0 



1-9 



l'8 



1-7 



1-6 



1-5 



1-4 



1-3 



1-2 



II 



10 



0-9 



20 15 10 5 



10 15 20 



n V 



in 



iv^ 



n 



^ m 



w 



Tliu females, althoui,^! icw, respoiul well to Brooks's law :— 098 X 1-17 = I'li;; 

 l-44xl-47 = 211. There were only three males at Stage IV., a uumher which cannot 

 be expected to yield a satisfactory mean ; the mean is too low to lit with the ratios 

 between Stages III. and 11. : 108xl-30 = 110; rj.0xl-30=r82. 



If the supposition that an older stage exists be correct, its female mean ^^ ill be about 

 3-10=:2-llXl-i7, and its male mean about 2-36=l-82xl-30. 



SKCOND SEKIES. — ZOOLOGV, VOL. X. 



15 



