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SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. I37 



Pennella the fast movement of the whales explains the long €:gg 

 strings. 



If the Caligus is not attached to a fish during the egg laying, but is 

 placed in a dish, the egg masses, because of lack of pull, assume the 

 peculiar appearance shown in figure 2. 



In the gill parasites such as the Chondracanthidae, mostly living 

 in the gill cavity of fishes, the water current is more constant, although 



Fig. 3. — Chondr acanthus lopliii Johnston, female with egg strings. 



the current will increase somewhat if the fish leaps as a result of being 

 irritated by the copepod ; because of these more vigorous movements 

 the fish needs more oxygen and therefore more water passing the 

 gills. In these gill parasites we therefore also find long, slender egg 

 strings, not, however, drawn out into a single string of pearls, but 

 a string several eggs thick (fig. 3). 



The Lernaeopodidae have a fixed attachment and therefore are 

 not able to irritate the fish. The shape of the egg strings in this case 



