572 CRUSTACEA. 



Found in a Tridacna, at Tutuila, one of the Samoan or Navigator 

 Islands. 



Length, one-third of an inch, the abdomen being inflexed; but, 

 with the abdomen extended, nearly two-thirds of an inch. 



Several of the characters of this species are given in the remarks 

 on the genus. The sides of the carapax curve around below, and 

 leave ventrally, between, a space about one-third the width of the 

 thorax. Abdomen when inflexed reaches to base of thorax. Eggs 

 were contained in the cavity formed beneath the inflexed abdomen. 



Antero-lateral angle of scale of second antennas acute. Base of 

 same antennas slender, last joint longer than preceding, flagellum 

 shorter than base. The superior antennae have a very stout base, 

 excepting the last two joints, which are very short. Length of hand of 

 first pair of legs about half that of carpus. 



Genus OEDIPUS, Dana. 



Pontonise affinis. Corpus depressum. Oculi permagni, rrmlto salientes. 

 Maxillipedis externi articuli toti latiuscidi, laminati, 3tio non angus- 

 tiore quam 2dus, ultimo non breviore quam 2dus. Rostrum sive 

 depressum, sive compressum et larninatum. Antennae, internal flagellis 

 duobus confectce. Manus 2dai scepius permagnce, longissimce, subequce. 

 Tarsi uncinati, breves, processu crasso infra armati. 



Near Pontonia. Body depressed. Four anterior feet chelate, second 

 pair the largest. Eyes quite large and much salient. Outer inax- 

 illipeds having all the joints equal, broad and laminate, third not 

 narrower than second, and fourth or last not shorter than second. 

 Beak either depressed or compressed and laminate. Hands of 

 second pair of feet usually very large and long, subequal. Inner 

 antennas ending in two flagella. 



The protuberance on the under side of the tarsus near its base, is 

 one characteristic distinguishing this genus from Harpilius, and sug- 

 gested the name of the genus, from ^v«, « swelling, * Wi , foot The 

 outer maxillipeds are remarkable for the breadth of all the joint?. 



