32 THE PRACTICAL FISHERMAN. 



is well known to every angler as an inhabitant of perch and jack, especially 

 the latter, during early season. Its body is covered by an oblong shield, 

 which, however, does not extend over the posterior part of the abdomen. 

 The mouth is armed with two styliform mandibles, and on each side 

 of the proboscis is a sucking disc, furnished with prehensile hooks for 

 attachment. There are four pairs of legs and a tail, which is a species of 

 swimmeret. The insect has the power of swimming rapidly and in a 

 straight line, but I have seen it turn rapidly over and over in a 

 most erratic manner when swimming. 



Belonging to the same tribe is the lernaea, which I have usually found 

 attached to the gills or fins of tench or roach. And I learn from an 

 American correspondent that it is the only parasite of the Coregonus 

 albus, or white salmon of the Canadian lakes and weirs. This animal 

 has a " long suctional proboscis ; a short thorax, to which is attached a 

 single pair of legs, which meet at their extremities, where they bear a 

 sucker, which helps to give attachment to the parasite ; a large abdomen ; 

 and a pair of pendant egg sacs." The males are particularly unlike the 

 females. "No one," says Dr. Carpenter, "would suppose the two to 

 belong to the same family, much less to the same species, but for the 

 microscopic study of their development." Some of the vegetable 

 parasitic diseases of fish are quite as prejudicial to the health of fish 

 as the internal, witness the salmon disease, which latter has been 

 identified as the saprolegnia, ferax. 



Having thus reverted to the diseases of fresh-water fish, I may notice 

 the manner of its natural death in passing. First, the movement grows 

 less rapid and energetic, and the fish seems occasionally to lose conscious- 

 ness, it grows weaker, now rolling with involuntary motion on its side, 

 or lurching head first. Finally it seems to be standing on its head, and 

 gradually topples over, floating belly upwards. It lives a little time, till 

 ab last the gill covers cease to move, and the fish is dead. Not very much 

 pathos in this, but sufficiently suggestive, however, of a similiar going 

 the way of all fish, flesh, and fowl. 



Of necessity much in this chapter is left unsaid that ought to have been 

 said. The idea is, however, to be suggestive rather than comprehensive . 



