308 CRUSTACEA. 



inner antennae are longitudinal, as in the Ocypods, to which they 

 have close relations ; but the body is very narrow in front, and 

 rounded tumid instead of quadrilateral. 



The following is a brief recapitulation of the characters of these 

 several families. 



CRUSTACEA GRAPSOIDEA. 



1. Articulus maxillipedis externi 4<us angulo 3tii interno articulatus. 



Fam. I. GONOPLACID^E. Carapax transversus. Frons quarta parte 

 latitudinis carapacis longior, paulo deflexus, lamellatus. Antennae 

 internae transversse. Articulus abdominis maris 2dus sterno con- 

 tiguo angustior. 



2. Articulus maxillipedis externi 4tus angulo 3tii apicali interno non articulatus sed 

 media marginis apicalis sive angulo externo. 



Fam. II. MACROPHTHALMID^E. Oculi tertia parte latitudinis carapacis 

 non breviores. Carapax subquadratus saepissime transversus, an- 

 tice latissimus, angulis anticis acutis, lateribus non arcuatis. An- 

 tennae internae sive transversae, sive longitudinales. Articulus 

 abdominis maris 2dus sterno contiguo angustior. Articulus maxil- 

 lipedis externi 3tius crista obliqua pilifera nunquam ornatus. 



Fam. III. GRAPSID^E. Oculi tertia parte latitudinis carapacis brevi- 

 ores. Carapax subquadratus, saspius depressus, lateribus aut rectis 

 aut arcuatis. Antennae internoe transversae. Articulus abdominis 

 maris 2dus sterno contiguo saepius vix angustior. Articulus max- 

 illipedis externi 3tius sive inornatus sive crista obliqua pilifera 

 ornatus. Palatum colliculo viae eflerentis limite instructum. 



Fam. IV. GECARCINID.E. Oculi breves. Carapax obesus, paulo trans- 

 versus, antice latus, curvatim declivis, lateribus arcuatis poneque 

 oculos large rotundatis, vix dentatis. Antennae internae transversae. 

 Articulus abdominis maris 2dus sterno postico vix angustior. Arti- 

 culus maxillipedis externi 3tius crista obliqua pilifera non ornatus. 

 Palatum colliculo viae efferentis limite non instructum. 



