ASSOCIATIONS 



607 



Conclusions 



Probably the most striking aspect of parasitism is the trend towards 

 morphological degeneration. In incipient parasitism, such as seen in the 

 copepod Caligus, the parasite differs only slightly from independent forms. 



Fig. 14.17. Developmental Stages in the Monstrillid Copepod 

 Cymbasoma rigidum (= Haemocera danae) 

 (a) Pelagic adult; (b) nauplius larva; (c) female parasite removed from its host; (d) 

 parasite in position in its host (Salmacina dysteri). (Redrawn from Malaquin (65).) 



It is somewhat more clumsily built and possesses a suctorial proboscis, 

 but still retains the ability to swim. Highly specialized species, such as 

 Xenocoeloma and Herpy/lobius, tend, however, to be little more than form- 

 less sacs, absorbing fluids from their hosts and concentrating on egg 

 production. As a general rule parasitism involves atrophy and finally 



