308 On the Classification of the Crustacea Choristopoda. 
Subtribus I. GAMMARIDEA. 
[Among the Gammaridea, the author finds that the posterior caudal 
stylets offer important characters for distinguishing natural groups or 
genera, and upon this ground, some new genera have been recognized 
mong the Corophide and Gammaride, and others that have been re- 
jected are sustained. ‘Thus Iphimedia is distinct ne Amphithoe, 
Mera and Dercothoe from Gammarus, etc 
Fam. I. DULIC HID. 
Gressorie, habitu Caprelloidez. Corpus lineare, epimeris obsoletis. 
Pedes posteriores longi, subprehensiles. Abdomen 5-articulatum. 
G.1. Duxicnta, Kréyer.*—Pedes 5ti 6ti 7 nee subzequi, 2di manu confecti. An- 
tenne quatuor longs, superiores prelo 
Fam. Il. CHELURIDZ. 
Corpus fere cylindricum, epimeris mediocribus. Abdomen segmen- 
tis 4to 5toque coalitis et oblongis, — inter se valde dissimilibus. 
G. 1. CHetura, Philippi.t 
Fam. Ill. COROPHIDA. 
Gressorize, pedibus partim lateraliter porrectis. Corpus plus minusve — 
depressum, seepe latum, epimeris perbrevibus, interdum obsoletis. Ab- 
domen forma appendicibusque normale. Antenne sepe pediformes. 
Subfam. 1. CLYDONINZ.—Styli caudales sex simplices, subulati. 
G. - Cxponta, Dana.t—Pedes filiformes, 5ti 6ti Tmique, longitudine increscentes, 
mi 2di non prehensiles. Antenne dus longie, crasse, rigide. 
Subfam. 2. COROPHIN &. —Antennx plus minusve pediformes. Styli eaudales 
1mi 2dique biramei. 
A. DIGITUS NULLUS 2-ARTICULATUS. 
1. Styli caudales 3tii os menor: 2di lmigue ramo externo eultriforms. 
G. 1. Cororanmm™, Z A fe ongiores et ee iores, flagello ning 
tes. Pedes 2di non on prehen Imis crassiores, ai feale a to latiore quam 5 hail 
G. 2. SrpHoneceres, Aréyer$—Antenne inferiores longiores, flagello racket 
Pedes 1mi Sdique “ibeatast [Pedes, a :tique articulo rie laté obcor 
Tubum lapillis fragmentisque rmatum inhabita 
* Tids. [2], i 81 2, 1846. 184 
{ Arch. Nat. 18 and @. J. Allman, Kon st Mag, BEL xi 6% June, 
Am Shee Ph viii, 140; Lcilius, D., 
ver ete., =, 1888-1840, pl. 20, t1; " Tidsekr. [2 2], i, 481, 1845. Kroyer ® 
MAA ined 2 Lo ee 
Bde” thoracici primi et 2di paris validissimi, tructi gar pce ; 
—— 3tii e t Ati ti paris 8 articulo primo latissim , laminari ; articulo quart co articulogue- 
caret hese see Sti 6tique paris mim ohinge swan recur 
Be han ungue_ farcato. Pedes ‘imi ome papa gc recurvatl, eit 
