Tribe 2. 



GAMMAEIDEA, 



rks. This tribe comprises the ordinary or typical Amphipoda 

 and constitutes by far the greater part of that order. Of course it must In- 

 divided into numerous subordinate groups, whicli however, do not bear exact I v 

 the same systematical relation to each other. Owing to the latter circumstance, 

 some of the later authors, for instance Boeck, only admit a verv restricted 

 number of true families, whereas some of the latter, and especially 1 lie family 

 (.htninidr'ulf?, have been again divided into numerous sub-families. . As there, 

 however, is far from being full concord among the authors about the limits 

 of the several families and sub-families established, I think it will be at 

 present more suitable to avoid such a complicated classification and to restrict 

 ourselves to a subdivision of the tribe into a number of families only, 

 remembering, however, that some of these families are rather nearly related. 

 while others are more sharply denned. 



Fam. ). Orchestiidae. 



Body now rather tumid, now more or less compressed, with the met a 

 some and urosome comparatively short and stout. (Y>xal plates rather large, 

 the 4th pair not emarginated posteriorly, f>th pair deeply bilobed. (Vphaloii 

 truncated anteriorly and having the buccal mass greatly projecting interiorly. 

 Eyes comparatively small and situated near the dorsal face of the ccphahm. 

 Superior antenna generally very much shorter than the inferior and without 

 any accessory appendage. Inferior antenme more or less pediform, peduncle 

 rather elongated and having its basal joint coalesced with the cephalmi. 

 Anterior lip large, rounded; epistome applanated. Posterior lip membranous, 

 with projecting lateral corners. Mandibles without palps, very powerful, cutting 

 edge divided into two superposed lamella 1 which arc strongly denticulated on the 

 edges, molar expansion large and thick; between both a series of curved setae. 



4 - Crustiu-o:i. 



