494 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 8» 



ARGULUS JAPONICUS Thiele 



Figure 32 



Argulus japonicus Thiele, 1900, p. 48; 1904, p. 39, figs. 94-98.— Wilson, 1902, 

 p. 727.— ToKiOKA, 1936a, p. 334, pi. 21, figs. 1, 2.— Yamaguti, 1937, p. 781, 

 figs. 1-9. 



Argulus trilineatus Wilson, 1904, p. 651, figs. 34-38.— Gtjbeelet. 1928, p. 35, 

 figs. 1-7.— Meehean, 1937, pp. 288-292, pi. 1. 



Carapace elliptical, covering third swimming appendages or reach- 

 ing fourth ; eyes well separated, cephalic area not very broad ; sinuses 

 shallow; abdomen small and spindle shaped; anal sinus deep, anal 

 furcae basal, sides flaring on female, not on male. Anterior respira- 

 tory area small, subtriangular, posterior one large and reniform 

 (fig. 32, &). The dorsal ridges are branched. Both males and females 

 have been reported up to about 6 mm. in length. 



Figure 32. — Argulus japonicus: a. Ribs of suction cups; b, respiratory areas; c, male 

 accessory organs of second, third, and fourth legs. 



Antennae small, an anterior knob on the base of the first pair, 

 spines at the base of both pairs and near the midline. Suction cups 

 with an elongate basal segment and five to seven imbricate plates in 

 the ribs (fig 32, a) ; marginal lappets about six or seven between 

 the ribs. Second maxillae with broad basal plate having blunt teeth 

 widely separated; spines near midline about the same size as the 

 teeth. 



Swimming appendages with flagella, posterior surface of coxa on 

 fourth appendage of female with fleshy rounded lobe. On the male 

 the second appendages have a bilobed posterior protuberance with 

 truncate spines along edge. It is placed somewhat obliquely across 

 the coxa with the mesial lobe more dorsal and the distal portion of lobe 



