FLEMINGER: INTEGUMENTAL ORGANS IN GENUS EVCALANUS 



Table 9. — Frequency of absence of perforations at 

 designated site in Eucalamts subieniiis (%). 



Table 10. — Correlation coefficient (/-) of TL and PN in 



adult females of Eucalanus. Original measurements shown 

 graphically in Figures 10. 12. 14. 16. 



genetic stage. In making such comparisons, 

 however, it should be recalled that considerations 

 limited to the numerical value of PN is mean- 

 ingful primarily within a species group. Be- 

 tween groups numerical differences in desig- 

 nated sites may not occur, but the species 

 always differ in topographic arrangement of 

 sets of perforations common to their respective 

 group (Figures 9, 11, 13, 15). 



Scatter diagrams of TL and PN (Figures 

 10, 12, 14, 16) show no common pattern of re- 

 lationship among the 19 distinguishable popu- 

 lations (i.e., including the three geographical 

 populations of auhtenids). Pearson's product- 

 moment correlation coefficients were calculated 

 for the available measurements of each popula- 

 tion (Table 10). Eleven were positive correla- 

 tions and eight were negative, a division in- 

 dicative of the absence of a real relationship 

 between TL and PN in the genus. Only four of 

 the correlations depart significantly from zero 

 (5% level): three are positive correlations and 

 one is negative. All aspects considered, the four 

 significant correlations, i.e., subtenuis, Pacific 

 Ocean (-I-), mucronatus { + ), sewelli { + ), and 

 mniiachus ( — ) are probably spurious. Thus, 

 as a working hypothesis PN and TL may be 

 considered to vary independently in adult 

 female Eucalanus. 



These data shed light on another vital question 

 involving TL and PN, namely, whether in fact 

 the two characters are related genetically. We 

 may anticipate that such a relationship would 

 be apparent by the correlation of the two charac- 

 ters in each species group. 



Figures 10, 12, 14, and 16 in fact clearly 

 show the absence of uniformity in the relation- 

 ship of TL and PN across the genus. We find 

 that each group presents a different pattern of 

 relationship between TL and PN. 



It would be of considerable interest to know 

 if PN relates to geographical overlap in the 

 breeding range of species of the same species 

 group. Another related question of ecological 

 significance is whether TL varies with the ex- 

 tent to which the range of a species falls outside 

 of the ecological or biogeographic regions 

 typically occupied by the species group. 



REMARKS ON THE FUNCTION OF 



INTEGUMENTAL ORGANS IN 



EUCALANUS 



With so few available retinal cells (Vaissiere, 

 1961; Fahrenbach. 1962, 1964; Park, 1966), 

 copepods must locate appropriate sexual part- 

 ners, couple, and accomplish spermatophore 

 transfer and attachment in the apparent ab- 

 sence of visual contact with the environment. In 

 nature the available methods appear to be 

 eminently successful in preventing hybrid pair- 

 ing and in ensuring functional placement of the 

 spermatophore's discharge canal on the female 

 genital pore (Fleminger, 1967; Frost and Flem- 

 inger, 1968). External chemical and mechanical 

 receptor-effector systems among the Crustacea 

 appear sufficiently diverse to provide adequate 

 non-visual channels mediating the exchange of 

 information required by a relatively complex and 

 efficient, instinctive mating behavior. As in 



1005 



