4 8 



BRITISH FRESHWATER FISHES 



lobster and may be three times as long as the 

 louse which carries them. 



The eggs hatch out as larvae, which swim freely 

 at the surface, and after a few months, in which they 

 change considerably, find their host and claw on to 



B. 



FIG. 8. A. Sea-louse of Salmon, female, about twice the natural size 



(after Scott), 

 c. carapace ; g. genital segment ; ab. abdomen ; e. egg-string. 



B. Gill-maggots of Salmon, females, about four times the natural size, 

 from the side (after Gadd) and from above (after Steenstrup and 

 Liitkeri). 



s. sucker ; a. arms ; <?. egg-cases. 



it ; after one or two months more they gain a new 

 attachment, a special frontal gland pouring out a 

 viscid secretion, which is pulled out into a thread 

 by a backward movement of the louse, and then 

 hardens, forming a strong and flexible connexion 

 which is not broken until the adult structure is 



