No. 399.] WORTH-AMERICAN INVERTEBRATES. 225 
Fic. 9. — Serolis carinata. Fic. ro. 
airs of legs, with penultimate joint or propodus dilated, and forming, 
with reflexible dactylus, a prehensile hand. All the epimera distinct. 
Chiridotea Harger 
a’. Sides of head entire and not laterally produced. Eyes lateral. Legs 
all ambulatory ; three anterior pairs with penultimate joint not or 
not much dilated. 
à. Flagellum of second pair of antennz well developed and multi- 
articulate. 
c. Palpus of maxillipeds four-jointed. Epimera of all the seg- 
ments well developed and evident in a dorsal view. Abdo- 
men (including the terminal segment) consisting of three 
segments with lateral sutures, indicative of another partly 
coalescent segment. . . +--+ =: - Idotea Fabricius 
¢. Palpus of maxillipeds not four-jointed. Abdomen consisting 
of one segment, uniarticulate. 
d. Palpus of maxillipeds th ee-jointed. All the epimera 
coalesced and perfectly united with the segments. 
Synidotea Harger 
d. Palpus of maxillipeds two-jointed. Epimera of second, 
third, and fourth segments coalesced and perfectly 
united with the segments ; those of the fifth, sixth, 
and seventh segments distinct and well developed. 
Colidotea Richardson 
2’. Flagellum of second pair of antenna not multi-articulate. 
c. Flagellum of second pair of antennae rudimentary. Second 
pair of antenna a little longer than first pair. 
Edotea Guérin- Ménéville 
g. Flagellum of second pair of antennz usually obsolete. Sec- 
ond pair of antenna much longer than first pair. 
