220 THE AMERICAN NATURALIST. [Vor. XXXIV. 
a’, Body relaxed, Head constricted at the base. Uropoda 
much shorter than terminal segment. Legs gradually 
much longer successively ; seventh pair abruptly 
verymuchso. . . . . . . . Olencira Leach 
a’. Head more or less immersed or set in the first thoracic segment. 
à. First pair of antennz contiguous at the base. 
c. Epimera of the first pair with a carina produced in the form 
ofa spoon. Ungulz very long, unequal in length; those 
of the third pair longest, abruptly longer than second pair. 
Terminal segment transverse. . . . Ceratothoa Dana 
c’. Epimera of the first pair not produced. Ungule mostly 
very short, very rarely long, equal in length. Terminal 
segment subtriangular, semicircular, often bilobed. 
Meinertia Stebbing 
2’. First pair of antennze manifestly distant at the base. 
c. Abdomen maniféstly separated from the thorax, abruptly 
narrower than thorax. . . . . Cymothoa Fabricius 
c. Abdomen contiguous with thorax, not narrower than thorax. 
Livoneca Leach 
Genus /Egathoa Dana. 
a. Surface of head smooth, evenly convex. Second pair of antenna ten- 
jointed. First thoracic segment longer than any of the succeeding 
segments, which are of equal length. 
A-gathoa loliginea Harger, M 
a’. Surface of head with central portion sharply raised above the lateral 
portion, which is deeply excavate just in front of the eyes. Second 
pair of antennz eight-jointed. First three thoracic segments sub- 
equal ; last four subequal, and somewhat shorter than first three. 
"Egathoa medialis Richardson, M, 3-25 fms. 
Genus Nerocila Leach. 
a. Terminal segment regularly rounded. Head subtruncate in front. 
Eyes distinct, black. . . . . . . Nerocila munda Harger, N 
a’, Terminal segment cordate, acuminate. Head rounded in front. Eyes 
_ indistinct, obscurely defined. - 
à. Uropoda scarcely longer than the apex of the terminal segment. 
Nerocila acuminata Schicedte and Meinert, GSM 
2’. Uropoda much longer than the apex of the terminal segment. 
Nerocila californica Schicedte and Meinert, D 
Genus Anilocra Leach. 
a. Terminal abdominal segment regularly rounded. All the epimera extend 
fully t i angies of their p li g segments. Branches 
of uropoda longer than terminal segment. 
Anilocra occidentalis Richardson, D, 19 fms. (See Fig. 7, P- 221-) 
a’. Terminal abdominal segment subcordate. Two first epimera reach the 
posterior angles of the segments ; last four do not reach the angles 
tU FP 
