REPORT ON THE PARASITIC COPEPODA 73 



Remarks. This species is closely related to Caligns isonyx, 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 parallel. 



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, Polypriou prognatJms, 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 1,70 mm long, 1,45 mm wide. Egg strings 3 mm long. 



Color (preserved material) a uniform yellowish brown. 



{interitus, wrecked, alluding to the host on which it is found.) 



