KEVIEW OF GEI^US ARGULUS MEEHEAN 



499 



on anterior appendages. Third appendages of male have an anterior 

 trianguLir flap from the distal edge of the coxa extending over the 

 basis; the posterior surface of the same segment is enlarged where 

 the socket is located (fig. 35, c). The socket itself is merely a shallow 

 cup with a fleshy lip around it on the posterior surface of the seg- 

 ment in contrast to the usual opening on the dorsal side. 



The peg appears as a fingerlike lobe curled mesially, with a second 

 lobe proximally and pressed up against it. They are both located 

 on the dorsal side of the segment in line with the end of the exopod. 

 There is a chitinous ridge around its base, as in other species. 



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FiGDEE 35. — Argulus funduli: a. Ribs of suction cups ; b, respiratory areas ; e, male 

 accessory organs of tliird and fourth legs. 



Smith's description of A. latus is not full enough to enable one to 

 determine whether he has established a true species. The specimens 

 of A. funduU and A. latiis in the National Museum seem to be iden- 

 tical in every respect. Both have a slight lobe on the mesial side of 

 the basal plate of the second maxillae, and they lack spines near the 

 midline between them. They have 15 to 22 imbricate plates in the 

 rim of the suction cups, with a slightly enlarged one at the base. 

 The respiratory areas are similar on the two; the posterior lobe on 

 the fourth swimming appendages of the female are alike. The 

 antennae have a slight indication of an anterior knob on both species, 

 with the spines at the base of the first antennae and the postantennal 

 ones larger than the others. The carapace reaches or covers the 

 third thoracic appendages. U.S.N.M. No. 60452 contained some 

 immature males labeled A. latus along with some females. The males 

 were immature so that the accessory copulatory apparatus was not 

 developed far enough to tell whether there were any specific differ- 

 ences. It is therefore proposed that until the males are found these 

 species be considered as synonymous. 



