2o6 STALK-EYED CRUSTACEA 



I. Pseudothelphusa. 



PsciidothelpJuisa . Saussure, Smith, Rathbun. 



Poiamia . . . Latreille, De Haan, Dana, Saussure. 



Boscia .... H. Milne Edwards, A.Milne Edwards. 



Hypoloboccra 1 ,-> , 

 -^^ Ortmann. 



PotanwcarcbiHS ' 



The posterior margin of the fourth joint of the ex- 

 ternal maxillipedes equals the anterior margin of the 

 third joint, against which it is applied. The external 

 appendage (exognath) is not as long as the third joint ; 

 efferent branchial channel without tooth or spine. The 

 superior margin of the front is less advanced than the 

 inferior margin, or about equally advanced with it ; 

 antero - lateral teeth small, often tuberculiform. The 

 terminal joint of the walking legs is styliform and has 

 five rows of small spines ; three upon its upper surface 

 and two below ; these rows can be traced backwards 

 on the other joints of the legs. 



Synopsis of the Species. 



I. Front sloping downwards, without line (superior 

 frontal border) indicating bend. 



A. Antero-lateral margin of carapace almost smooth. 

 Lower margin of front strongly rimmed, convex. Walk- 

 ing legs not slender. — [P. aiuericaiia.) 



II. Front sloping downwards, with a superior frontal 

 border that is not strongly indicated. 



B. External appendage of external maxillipedes re- 

 duced to a stump. 



a. Superior frontal margin unilobate. — {P. dcnticulata.) 



