REPORT ON THE PARASITIC COPEPODA 73 
Remarks. This species is closely related to Caligus tsonyx, but differs 
markedly from it in the proportions of the various body regions, particularly 
the free thorax segment. The rudimentary endopod of the first legs is larger 
than in any other known species of the genus, and the furca is longer and 
narrower, while its branches are divergent instead of paralle!, 
The host is manifestly not a common one since it was unknown both to 
the members of the expedition and to the natives at the time it was captured. 
The same host, when taken again, will doubtless yield more of the species. 
(aesopus, odd-footed, in allusion to the rudimentary endopod on the 
first legs.) 
Lepeophtheirus interitus, new species. — Plate 4 fig. 14—17. 
Host and record of specimen. A single female with egg strings was 
taken from the gills of the wreckfish, Polyprion prognathus, at Juan Fernandez 
(Masatierra), April 23rd., 1917. This specimen becomes the type of the new 
species. 
Specific characters of female. Carapace definitely more than half the 
length of the whole body, as wide as long, evenly rounded anteriorly, some- 
what squarely truncated posteriorly. Posterior lobes rather narrow and not 
quite reaching the level of the median lobe. Thoracic area five-sevenths of 
the width of the carapace, cephalic area narrower, somewhat quadrangular, its 
anterior corners quite: pronounced. No eyes visible. 
Free segment half the width and a third of the length of the genital seg- 
ment, its lateral- margins strongly convex. Abdomen one-third the length of 
the genital segment, one-jointed; anal laminae short, incurved toward each 
other, each armed with four setae. Genital segment elliptical, a little longer 
than wide, with short and blunt posterior lobes, its sides strongly convex. Egg 
strings more than half the length of the body and a little wider than the ab- 
domen; eggs rather thick, about twenty in each string. 
Frontal plates well defined; first antennae short, not reaching the level 
of the lateral margin of the carapace; second antennae rather stout, the term- 
inal claw strongly curved. 
First maxillae large and deeply cleft, the two branches about the same 
length, the inner one somewhat thicker. Furca narrow, about twice as long 
as wide, cut beyond the center, the branches conical and widely divergent, the 
base smoothly rounded. 
First swimming legs with the rudiments of an endopod on the distal, 
posterior corner of the basal joint. Fourth legs large and long, reaching nearly 
to the posterior margin of the genital segment. 
Total length 5,50 mm. Carapace 2,95 mm long, 2,90 mm wide. Genital 
segment I,7o mm long, I,45 mm wide. Egg strings 3 mm long. 
Color (preserved material) a uniform yellowish brown. 
(¢xter?tus, wrecked, alluding to the host on which it is found.) 
