REVIEW OF GENUS ARGULUS MEEHEAN 477 



ff'. First two pairs of swimming appendages with 

 flagella. 

 7i\ Conspicuous anterior hook on first antennae, 

 antennae short, broad spine at base of first 

 antennae and broad postantennal spine ; second 

 maxillae broad and short with spinous pads 

 over ventral surface, postmaxillary spines short 

 and truncate, anterior pair on papillae; salt 



water. Pacific coast $ pugettensis (p. 487) 



H?. Knob present on anterior surface of first anten- 

 nae ; dorsal ridges branched at anterior end ; 

 posterior respiratory area somewhat reniform ; 



fresh water, universal japonicus (p. 494) 



<?. Basal plate of second maxillae lobed. 

 &. Lobes of second maxillae truncate ; hook present on 

 anterior surface of first antennae ; supporting ribs of 

 suction cups composed of rods. 

 f'. Lobes of second maxillae appearing worn, postmaxil- 

 lary spines truncate and inconspicuous, anterior 

 knob on first antennae long and fingerlike, with 

 slight anterior hook ; supports of suction cups com- 

 posed of 3 straight rods; salt water laticauda (p. 495) 



f. Basal plate of second maxillae with truncate or 

 rounded teeth, postmaxillary spines conspicuous ; 

 supports of suction cups composed of 4 or 5 rods ; 

 posterior respiratory area reniform, anterior hook 

 on first antennae stout ; fresh water, Congo River, 



Africa reticulatus (p. 497) 



e". Lobes of second maxillae not truncate. 



/\ Two pairs of postmaxillary spines missing, proximal 

 lobe of basal plate more distinctly separated than 

 the one or two lateral ones ; respiratory areas small 

 and widely separated; suction cups with about 16 

 plates in supporting ribs with a proximal plate 

 slightly longer than the others; anterior knob of 

 antennae almost wanting; swimming appendages 

 without flagella ; salt water. New Orleans to New 



Brunswick funduli (p. 498) 



f. Two pairs of postmaxillary spines present. 

 g^. Lobes of second maxillae and postmaxillary spines 

 very broad with spinous papillae on them ; sup- 

 ports of suction cups with one long and one oblong 

 rod ; spines at base of first antennae and post- 

 antennal spines extremely broad and blunt, ante- 

 rior hook broad at base and very long; anterior 

 respiratory area very small and posterior one 



extremely long; fresh water, Uruguay violaceus (p. 500) 



flr*. Edge of basal plate of second maxillae with broadly 

 rounded lobes, mesial lobe somewhat more promi- 

 nent, postmaxillary spines very blunt and short ; 

 knob present on anterior surface of first antennae, 

 distal segment opposed by a spine, second antennae 

 without much enlargement of basal segments, 



