FISHERY BULLETIN: VOL. 7L NO. 4 



Table 8. — X^ test for homogeneity of frequency of absence of perforations from designated sites among geographically 

 different samples of Eucalanus siihtenuis adult females described in Figures 20 and 21. 



are the unmistakable phenetic expression of the 

 genotype. 



Body size (TL) is a priori also under genetic 

 control, and probably in copepods this control 

 is rigorous (Brooks and Dodson, 1965; Brooks, 

 1968; Dodson, 1970; June and Carlson, 1971). 

 However, it is known that in addition to selec- 

 tion pressures diet and temperature may strong- 

 ly influence size determination (Coker, 1933; 

 Deevey, 1960, 1964, 1966; Omori, 1970). A 

 question of immediate concern is whether TL 

 and PN may be sufficiently related to show 

 similar phenetic patterns of variation. 



Morphogenesis during the copepodite phase 

 of ontogeny appears to affect PN in a simple 

 predictable fashion. In general, copepodid stages 



III, IV, and V were found with the same num- 

 ber and arrangement of sites, segment by seg- 

 ment, as they appear in adults of the species 

 with exceptions in abdominal segments as 

 indicated above. The exceptions noted are 

 restricted to ontogenetic modifications in the 

 addition of abdominal segments and subsequent 

 fusion of segments brought on by sexual matu- 

 ration. Thus at least during the second half of 

 ontogenesis integumental organs maintain 

 numerical and distributional relationships 

 during typical size increases associated with 

 moulting; no observations are available for 

 copepodite stages I and II. If a relationship 

 exists between TL and PN it should be apparent 

 from comparison of the two within a given onto- 



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