CHALIMUS. 
279 
Kroyer seems disposed to consider it merely as the 
young of a Caligus, but farther observations are necessary 
to confirm this. The general appearance is that of a 
Lepeoptheirus ; but we can trace four distinct articulations 
in the thorax, and three in the abdomen. 
The frontal plates are well developed, and want the 
small lunules or sucking- discs on the lateral portions ; 
but instead of these, have arising from the central part of 
its anterior margin a long and slender organ, rather in- 
distinctly articulated at its base, and terminated by a 
round expansion like a sucker, by which it fastens itself 
to the body to which it is found attached. The presence 
of this organ would lead us to suppose that this animal 
must lead a much more sedentary life than the rest of the 
Caligidae ; and it would appear in this respect to connect 
it with some of the Lerneadae, which we shall find to 
possess a somewhat similar organ of prehension. 
1. Chalimus scombri. Tab. XXXIII, figs. 5, ha, b. 
Chalimtjs scombri, Burmeister , Nov. Act. Acad. Nat. Cur. Bonn., 
xvii, 294, t. 23, f. 13. 
— Kroyer , Tidsskrift, ii, t. 1, f. 1. 
— M. Edwards , Hist. Nat. Crust., iii, 457. 
Description . — Carapace elongated oval, somewhat nar- 
rower at the anterior extremity, and then gradually 
becoming broader posteriorly. Frontal plates large, well- 
developed, and prominent. Thorax composed of four 
distinct segments. Abdomen large, and consisting of 
three joints ; the last terminated by two tolerably-sized 
caudal plates, each sending off three or four short setae. 
Hab. — Belfast Bay, attached to a Caligus Muller i, 
W. Thompson, Esq. 
