374 
CLASS CRUSTACEA. 
tlie following are terminated by two long digits ; the others 
are in the form of membranaceous leaflets. Caligus prodiic - 
tus, Mull. Entom. xxxi. 3, 4; Monoculus Salmoneus , Fab. 
The last subgenus of this subdivision, that of 
Anthosoma, Leach , 
Approaches the preceding, as far as the existence of a siphon, 
and that of the two filaments at the end of the tail ; but is re- 
moved from it, as well as from those which precede it, by rea- 
son of two of its antennae, carried forwards, in the form of small 
monodactylous claws, and of the last six feet, which are mem- 
branaceous, joined inferiorly, and folded laterally on the post- 
abdomen, so as to form a case to envelope it ; those of the 
first and third pair are unguiculated ; the second are termi- 
nated by two short and obtuse digits. Anthosoma Smithii , 
Leach, Dcsm. Consid. 1 . 3 ; Caligus imbricatus , liisso. 
In others the body is oval, without projecting appendages in 
the manner of a tail, composed of filaments, or of appendages 
in the form of lines, at its posterior extremity. A portion of 
the upper teguments forms at first, and in front, a buckler, 
not covering its anterior moiety, being more narrow, rounded, 
and emarginated anteriorly, widened, and, as it were, bilobate 
at the other end ; then come successively three other pieces, 
or scales, rounded and emarginated posteriorly ; the second 
of which, the smallest of all, is almost in the form of an in- 
verted heart, and the last and largest is vaulted. The four 
posterior feet are in the form of laminse, and united by pairs; 
those of the first and third are unguiculated; the second 
have their extremities bifid. The siphon is apparent. The 
eggs are covered by two oval pieces, contiguous, coriaceous, 
placed under the abdomen, and exceeding it in length. 
Such are the characters of the genus 
