REVIEW OF GENUS ARGULUS MEEHEAN 



513 



plied with setae. Suction cups about one-fifth width of carapace, rim 

 supported by ribs with two segments, edge with truncated lobes armed 

 with delicate setae as opposed to triangular lobes of other species (fig. 

 43, «) . Second maxillae with blunt teeth and two pairs of blunt post- 

 maxillary spines near midline. 



FiGURB 43. — Argulus appendiculosus: a, Ribs of suction cups; b, respiratory areas; c, 

 male accessory organs of last three legs. 



Swimming appendages with flagella, female with boot-shaped 

 lamella posteriorly, which extends beyond the margin of the abdo- 

 men; on the male the lamella is prolonged and turned anteriorly 

 so that the end is parallel with the anterior edge of the fourth ap- 

 pendages. The second appendage of the male has a broad lobe on 

 the posterior ventral edge of the coxa, which is slightly prolonged 

 laterally with long setae on it (fig. 43, c). On the third appendage 

 the coxa has a triangular lamella extending over the basis and a 

 posterior one also projecting laterally. The posterior surface of 

 the basis beneath the lateral lobe of the posterior lamella is slightly 

 enlarged to accommodate the socket with its opening directed dor- 

 sally. The basal joint of the endopod of the fourth appendage is 

 broad and the terminal joint abbreviated on most mature males. 

 The peg consists of a typical pear-shaped organ with a narrow tip 

 directed laterally; around the base is the usual chitinous ridge run- 

 ning obliquely across the basis; posteriorly this segment is rounded 

 into a lobe. The posterior lamella has already been mentioned. 



The hosts and localities are as follows: Sucker {Catostomus sp.), 

 Montpelier, Vt. ; Ictalurus pimctatus, grunt, Cumberland Falls, Ky. ; 



