CRUSTACEA. 
117 
Akceus (Pbasisa) ceecliata. — Besmarest, Consid. sm. Crust., p. 284. 
This is the female, probably, of Anceus maxillaris. 
These two animals for a long time were considered as repre- 
senting two distinct genera, and by some as separate families, 
their habits and appearance are so unlike each other. It now 
appears from the researches of M. Hepe, of Brest, who has the 
honor of first determining their relative connection with each other 
to he male and female. In early life the two resemble each other 
very closely, and they then live as parasites on the external surface 
of fish ; as they grow older the male assumes the form of Anceus, 
and the female continues unaltered in the form of Pranisa. After 
quitting their parasitic mode of life they appear, as far as we 
can judge, particularly the male, to live without eating, for it 
has no mouth, and the mandibles are placed in the front of the 
head like antennse. The female appears to exist as a huge ovi- 
sac, and when the young are matured the mother appears to be 
empty, and almost devoid of the traces of internal organs. The 
life of both male and female now appear, as far as usefulness is 
concerned, to be over, for although I have kept them alive for 
months in this condition they never appear to change, or seek or 
obtain food, but lie motionless and feeble. 
ISOPODA NOEMALIA. 
BOPYRIBJE. 
Genus, Bopyrus. — Latrielle. 
Male. Small, narrow ; antenute rudimentary. 
Pemale six times as large as the male. Pearshaped, unsymet- 
rical. Body much flattened. 
Bopyrus squillaeius. — Latrielle, Hist. Nat. Crust., vii,p. 56, t. 59, 
/. 2 . — Bate and Westwood, p. 218. 
Frequently found under the shell of prawns and shrimps. 
Brom Polperro and off the coast. 
Genus, Pheyxus. — Itathhe. 
Male. Very minute and elongated, head transversely minute, 
''^ith two dark minute eyes. 
Female. Large inert nearly globular mass, with the segments 
scarcely indicated by depression s, with wide and oviparous plates. 
