No.noi. PARASITIC C0PEP0B8—CALIGIDJE— WILSON. 633 



Furca small with parallel branches separated by a V-shaped sinus 

 reaching- beyond the center. The shape varies slightly in the speci- 

 mens from the two localities as indicated in the figures. First swim- 

 ming- legs short and stout, the basal joint with a stout spine on its 

 posterior border, the two inner terminal claws pectinate. 



Exopods of the second and third legs armed with long and stout 

 spines. Fourth legs of medium size, the basal joint about as long as 

 the other three and bearing a single small spine on its outer margin near 

 the distal end. A very long and slender spine at the distal end of the 

 second joint, a shorter and stouter one on the third joint, the two inner 

 terminal claws pectinate, the outer one very long and slender. Fifth 

 legs large and well denned as already described, protruding for more 

 than half their length beyond the posterior margin of the genital seg- 

 ment. They are broad at the base, but taper to a narrow tip, with the 

 plumose setae on the terminal half. This arrangement is totally dif- 

 ferent from that in any other species, except parviventris, and may be 

 used to great advantage in determining the species. 



Total length, 3.5 mm. Length of carapace, 2.3 mm. ; width of same, 

 2.3 mm.; length of genital segment, 1 mm.; length of egg strings, 2 

 mm. ; 15 to 30 eggs in each. 



Color a uniform dark yellow without pigment spots. 



(dissimulatus, dissimulo, to conceal what really exists.) 



Male. — Carapace similar to that of the female. Free thoracic seg- 

 ment relatively much larger, fully as wide as the genital segment and 

 nearly half as long, with the bases of the fourth legs protruding as 

 prominently as in the female. 



Genital segment elliptical in outline, about as wide as long, and 

 squarely truncated posterior^. The fifth legs appear as a pair of 

 prominent papilla? projecting from the posterior lateral margin on 

 either side, each papilla carrying three long spines. 



Abdomen very short, wider than long; anal papilla? large and armed 

 with plumose seta? even longer than those in the female. 



The second antenna? are much longer than in the female and branched 

 several times like a stag's horn; the}^ evidently make effective clasping 

 organs. The other appendages are as in the female, except the fourth 

 legs, which are relative^ much larger and stouter. 



Total length. 2.5 mm.; length of carapace, 1.7 mm.; width of same, 

 1.6 mm.; length of genital segment, 0.37 mm.; length of abdomen, 

 0.2 mm. 



The National Museum collection consisted of one lot, 1505, taken 

 from the white-spotted serranus, Etpinephelus lahriformis^ at Charles 

 Island, one of the Galapagos group. This lot includes a male with 

 ten females, but the latter were not very well preserved, and hence 

 the author was much pleased to receive a second lot of four females, 

 admirably preserved, which had been taken from a red grouper, 



