950 CRUSTACEA. 



The stylets are all long ; the first pair extends a little beyond the 

 others. 



Gammarus albidus, Dana, Proc. Amer. Acad. Sci. ; ii. 210. 



2. Abdomen dorso non spinulosum nee dentatum. 



Gammarus tenuis. 



Gracilis, epimeris angustis. Caput fronte laterali prominulum. Oculi 

 rotundati, parvi. Antennas lmce corpore paulo breviores, teretes, tenu- 

 issimas, articulo primo longo, secundo duplo longiore quam tertius; 

 flagello basi parce longiore, 14c-articulato, setis longioribus quam arti- 

 euli, appendice brevissimd. Antennas Idas valde breviores, setis longi- 

 oribus; basi valde longiore quam basis lmarum, articulis 2 ultimis 

 longis, submquis, precedentibus perbrevibus; flagello 6-articulato, non 

 longiore quam articidus basalts ultimus. Pedes antiei inediocres, manu 

 oblongd, apice paulo latiore et paulo obliqud truncatd palmam efficiente, 

 palmd non excavatd, angulo infra finiente, digito mediocri; secundi 

 dimidio nninores. Pedes sex ultimi valde inasqui, Imi Qtis nmlto lon- 

 giores, setis sparsis, longiusculis. 



Slender, epimerals narrow. Front margin of either side of head a 

 little prominent. Eye round, small. Superior antennae somewhat 

 shorter than the body, very slender, terete, first joint longer than 

 third, and second twice longer, flagellum slightly longer than the 

 base, fourteen-jointed, setae longer than joints, appendage very short. 

 Inferior antennae much shorter, setae longer, base much longer 

 than base of superior, last two joints long and subequal, the pre- 

 ceding very short, flagellum five-jointed, not longer than last basal 

 joint. Anterior feet of medium size, hand oblong, somewhat larger 

 towards apex and obliquely truncate, margins setose in tufts, an 

 angle at lower limit of truncation, palm not excavate, finger about 

 half as long as hand. Second pair much smaller than first. Last 

 three pairs of feet very unequal in length, seventh very much 

 longer than sixth pair. 



Plate 65, fig. 5 a, animal, enlarged ; b, part of palpus of mandible ; 

 c, hand of first pair. 



