PELAGIC AMPHIPOD — BOWMAN AND McCAIN 



9 



(t=2.6) but small compared to theii- divergence from the oceanic 

 population. Note that in this character the Puget Sound population 

 is intermediate, whereas the Revillagigedo Channel population was 

 intermediate mth respect to the cyphos index. 



6 7 8 9 10 II 12 13 14 15 16 17 18 19 20 

 TOTAL LENGTH (mm) 



Figure 7. — Ratio of length of basal process to that of distal segments in pereopod 5 plotted 

 against body length in oceanic (circles), Puget Sound (solid squares), and Revillagigedo 

 Channel (triangles) populations of Cyphocaris challengeri. 



Ratio of length of 3rd uropod to length of telson. — In figure 

 9 the ratio of the length of uropod 3 to that of the telson is plotted 

 against body length. Altho there is considerable variation, it can 

 be seen that the ratio decreases from 1.4-1.8 in juveniles to 1.0-1.2 in 

 adults. The rate at which the ratio decreases is approximately 

 equal in all three populations, but for a particidar body length the 



