STALK-EYED CRUSTACEA 447 



more gill plumes attached to the body wall on each 



side. 



Range. — South America. — {Parastacns.) 



This family and their genera are mentioned as they 



may be found in the fresh water of the countries under 



consideration. 



Tribe III. Stenopidea. 



Stenopidea . . . Spence Bate. 



A laterally compressed rostrum. First three pair of 

 legs armed with pincers, of which the third pair is the 

 largest and longest. 



One family. 



Family Stenopidae. 



Ste}iopidce , . . Spence Bate. 



Gills attached to the first joint of the first maxillipede. 

 Of the gills attached to the body wall, the posterior plume 

 is the largest. The external appendage of the external 

 maxillipedes is small, slender, and almost rudimentary. 



I. Stenopus. 



Stenopus . Latreille, Desmarest, H. Milne Edwards, 

 Dana, Spence Bate. 



The internal antennas have two flagella. The external 

 antennae have a long, flat, and obtusely pointed basal 

 scale, the apex being continuous with the external margin. 

 Flagellum long and slender. Mandible furnished with a 

 three-jointed palp, of which the last joint is the longest. 

 The third maxilla terminates in a sharp finger. The 

 first pair of maxillipedes is short, six-jointed, furnished 



