REVIEW OF GENUS ARGULUS — MEEHEAN 



517 



laterally almost to the base of the endopod. The basis has a slight 

 posterior rounded prominence with a few setae. The peg is set firmly 

 on the anterior distal edge of the basis near the base of the exopod. It 

 has the usual chitinous ridge running obliquely across the segment 

 around its base; two rounded papillae indicate the opening of the 

 ejaculatory duct at the end of the thorax. On the thorax of the male 

 between the second and third swimming appendages is a pair of tri- 

 angular flaplike structures, with the points of the flap directed 

 anteriorly on each side of the body near the base of the appendage. 



Length of female up to 25 mm., males about 16 mm. The hosts are 

 the alligator gar (Atractosteits tristoechics) , from Louisiana, Texas, 

 and Mississippi, and the long-nosed gar {Lepisosteus osseus), from 

 Ocean Pond, Lake City, Fla. 



ARGULUS BICOLOR Here 



FlGtJEE 46 



Argulus Ucolor Beee, 1936, p. 580, pi. 2, figs. 17-23. 



Carapace longer than wide, rounding forward into lateral sinuses, 

 cephalic area projecting forward prominently, posterior sinus broad ; 

 alae reaching fourth swimming appendages of female, extending onto 

 abdomen in male ; last thoracic segment broad, attached to abdomen 

 by a slender neck; anterior respiratory area small, slightly oblong, 

 posterior one about the same width, three times as long and slightly 

 curved (fig. 46, a). Abdomen about one-third covered by carapace 

 in male, anal sinus nearly half its length, papillae inconspicuous; 

 anal sinus of female more than half the length of abdomen. 



FiGDBE 46. — Argulus hicolor: a, Respiratory areas ; 6, ribs of suction cups ; c, male 

 accessory organs of last three legs. 



