Zoology. 289 



G. 2. Plagitsia, LatrJ^ — Corpus minus depressum, crassius. Ar- 

 ticulus maxillipedis exlerni 3tius apice 2di vix angustius, raro 

 longior quam laiior. Ramus maxillipedis Imi inlernus apice 

 transversus, 



Fam. IV. GECARCINIDiE. 



Oculi breves. Carapax obesus, paulo transversus, antice latus, cur- 

 vatim declivis, lateribus arcuatis poneque oculos large rotundatis, vix 

 dentatis. Antennae internee iransversse. Articulus abdominis marls 

 2dijs sterno contiguo vix angustior. Articulus maxillipedis externi 3tiiis 

 costa obliqua pilifera non ornalus. Palatum linea elevata via; effereatis 

 limite non instructum^ 



-I 



1. UCAINyE, Articulus maxillipedis externi 4tus apertus. 



1. Maxillipedes externi non kiantes. 



G. 1. UcA, Leach. — Articulus maxillipedis externi 4tus angulo 3tii 



exlerno insitus. 

 G. 4. Gecarcinucus, EdwA — Articulus maxillipedis externi 4tus 



marginis medio apicalis 3tii insitus. 



2. Maxillipedes externi rhomhoidice Mantes. 



G. 3. Cardtso^ia, Lair. — Articulus maxillipedis externi 4tus apice 



3tii exlerno itisitus. 

 G. 4. Gecarcoidea, Edw. — Articulus maxillipedis externi 4tus 



marginis medio excavato apicalis 3lii insitus- 



2. GECARCININ^E. Articuli maxillipedis externi 4tus et sequentes 



Stio celatus. 



G. 1, Gecarcinus. 



Fam. V. PINNOTHERID.E. 



Oculi breves, orbitis insiti, raro non retractiles. Carapax sive obesus 

 sive depressus, raro paulo oblongus et interdum parce rostratus, laleri- 

 Dus valde rolundatis. Antennee interna; aut transversse aut obliquse. 

 Abdomen maris anguslum, versus basin sterno contiguo valde an- 

 gustius. [Species omnes parvse.j 



2. PINNOTHERIN^. Articulus maxillipedis externi 2dus parvulus 

 aut obsoletus. Corpus sive obesum sive depressum. 



Plagusia and Philyra of De Haan, Faun. Japon., p. 31 ; the latter genus in his 

 jstem including Plagusia depressa of autbor.s and the former the P. sguamosa. The 

 distinction between his two irenera consists in this ; the palpus of the outer maxilU- 

 Peds in Plagusia has a fiageUum, and that of Philf/ra. none. The name Phtlt/ra 

 ^ionga to another genus of earlier date, instituted by Leach ; moreover, the re:=ejii- 

 biance between the species of these groups is so close in other characters, tliat we 



dims 



Seeies, VoL XU, No. 35.— Sept., 1851. 37 



