926 



CRUSTACEA. 



much prolonged beneath the fourth joint. The carpus of the second 

 pair has a narrow prolongation below, between the hand and the third 

 joint ; the third joint is not longer than the carpus ; the hand is a 

 little pubescent below. The caudal stylets, as in the other sex, have 

 the branches subulate, and the extremity appears almost to be the 

 continuation of the stylet instead of a separate spine ; the first pair 

 extends farther back than the second, and the second farther than the 

 third; the branches of the first pair have two or three spinules on the 

 upper side. The inner maxillae have nearly the usual form (fig. 1 h). 

 The inner lamellae of the maxillipeds are not half as long as the first 

 free joint of the maxilliped; the five joints of these organs have a few 

 very short setae on the inner side; and on the penult joint on the inner 

 side near tip there is a thick pubescence. 



Subfamily GAMMARINiE. 



The mandibles in the Gammarinae, unlike those of the Lysianas- 

 sinae, have a multidentate summit, and also, a broad inner lobe or 

 process, arising from just below the apex, which is similarly dentate 

 above. Below this lobe there is an oblong line or crest covered with 

 curving setae, and in some instances this surface is furnished with a 

 series of subparallel, dentate lamellae, approximately parallel to the 

 lobe above. Below this, there is a broad molar tooth, with a scabrous 

 or striated surface. 



The carpus of the second pair of legs in the true Gammarinae, as 

 far as examined, is not so narrow and small as to be intercepted 

 below by the fourth joint (that preceding), as happens in all the 

 Orchestidae, excepting a few Allorchestes ; and this character as well 

 as the oblong posterior stylets and the mandibular palpi, will gene- 

 rally distinguish those species having the superior antennae the shorter 

 from the Allorchestes. 



Gentjs IPHIMEDIA (Rathke), D. 



Epimerce magna, Uob rnaximce, btis valde brevioribus. Maxillipedes lati, 

 lamellis intemis grandibus. Styli caudales postici biramei, rmms 

 oblongis consimilibus, apice setigeris et nm wicinatis. Antenna lmce 

 scepius breviores. 



