936 CRUSTACEA. 



and the species thus differ widely from the Gammari and other related 

 genera. The two branches of the first and second pairs of stylets 

 in the species are usually very nearly similar, and are furnished nearly 

 alike with spinules. But in the A. brevipes (in which the lower 

 antennae are subpediform), one of the branches is styliform, and the 

 other lamellar, the latter being placed with an edge upward, and 

 edged above with numerous spines. 



The inner lamellar process of the second joint of the maxillipeds is 

 usually very long, reaching sometimes nearly to the base of the last 

 joint of these organs, and its margin is often furnished with a row of 

 spinules. The mandibular palpi are three-jointed, the first joint 

 short, and the last about as long as the preceding ; there are longish 

 setae at apex and below, which setae are setulose. The tarsus of the 

 legs has often (if not always) the seta of the under side obsolete. 

 Other characters will be gathered from the details given under some 

 of the species. 



The females may generally (always?) be distinguished by their 

 having the fingers of the hands short (not shorter than half the hand), 

 and the two pairs subequal. 



It may be that species exist having the posterior stylets and epi- 

 merals of Amphithoe with the superior antennae of Gammarus ; and, 

 if so, it may be a question whether the character of the antennae 

 should not be disregarded, and all be included with Amphithoe. 



Amphithoe rubella. 



Corpus crassiusculum, epimeris latis. Antennas lines dimidio corporis 

 longiores, articulo 2do valde longiore, flagello fere duplo longiore quam 

 basis, ferine 14:-articulato, articulis long is, setis perpaucis, brevibus; 

 lmce 2dis breviores, basi valde longiore quam basis lmarum, articulo 

 quarto longiore et flagellum fere cequante. Manus prima parva, ob- 

 longa, angusta, apice angustiore. Manus secunda valida, lata, sub- 

 rectangulata, apice (palma) transverso, parce excavato, angulo infero 

 promiuulo et acuto, digito mediocri. Pedes 3tii 4:tique breves; 6ti 

 Imique subwqui, 5tis valde brevioribus, setis spar sis, articulo primo 

 latiusculo. 



Body rather stout, epimerals broad. Superior antennae longer than 



