GAMMARIDEA. 



837 



longitudine vix superantes, articulo tertii longiore, tribus ultimis par- 

 vulls, subcequis. 



Body depressed, linear, head quadrate, abdomen posteriorly rounded. 

 Four anterior feet similar; the first pair the smaller; fifth pair 

 shorter than fourth, first joint not setigerous; seventh long and slen- 

 der; first joint setigerous on posterior margin, setae rather long and 

 plumose. Antennae subequal ; superior a little the smaller, seven- 

 jointed, the first joint longest ; inferior rather stout, seven-jointed, 

 about one-fourth as long as body, third joint longest ; last three 

 quite short and subequal. 



Plate 55, fig. 8, animal, imperfectly figured, enlarged, the caudal 

 extremity not finished. 



Harbour of Eio Janeiro, near the city. Collected, December 22 

 1838. 



Length, nearly one line. Head longer than the two following seg- 

 ments, nearly square in a vertical view ; in a lateral view largest pos- 

 teriorly. Extremity of abdomen nearly as broad as thorax. Eyes 

 small, with few facets, round, distant, black. Inferior antennae with 

 a whorl of short setae at apex of each of the last four joints. The 

 last three joints together about as long as either of the two preceding. 

 The anterior four feet have a few short hairs on the joints. The claw 

 is but slightly curved. There are plumose setae on the first joint of the 

 seventh pair of legs; also, a few on posterior margin of same joint of 

 sixth pair; but none, or not more than one or two, on fifth pair. The 

 first pair of stylets extends backward farther than the second, and 

 the second pair farther than the third pair. 



Genus PLATOPHIUM, Dana. 



Cephalothoi-ax anguste ellipticus, abdomine sub ventre bene inflexo, capite 

 subquadrato, oculis ad angulos anticos insitis et scepe paulo prominen- 

 tibu8. Antennas inferiores paulo longiores, totce bene pediformes, fla- 

 gellis perbrevibus sazpe confectce. Pedes 4 antici subchelati, 2dis valir 

 dioribus. Styli caudales Stii niinuti, simplicissimi, extremitate abdo- 



210 



