CIROLANA. 
249 
five rings of abdomen in general well developed and almost 
always distinct from each other ; the last false legs termi- 
nating in two plates. Head generally small. First three 
pairs of legs generally (or sometimes all) with a strong claw, 
enabling most of the species to attach themselves to fish and 
to hold on. 
Most of the species are more or less parasitic, being at- 
tached to fish, to which they can adhere by means of their 
strongly-hooked legs. In some parts of the United States'* 
the fishermen say that the fish-lice are “ necessary to the 
life of the fish, and as a proof of it, they observe that if the 
louse be taken from him, the fish will die, although thrown 
into the water ; but it is probable that the death of the fish 
is not owing to the removal of the parasite, but to its being 
withheld too long from the water.” 
Gen. 128. CIROLANA, Leach. 
Abdomen six-jointed. Eyes granulated. Small plates of 
the posterior ventral appendages larger and wider than the 
inner. The legs have very small claws, and are adapted for 
walking. 
Cirolana Cranchii, Leach. (Plate XIV. fig. 3.)— 
* Say, Journal Acad. Nat. Sc. Phil. i. p. 396. 
