REVIEW OF GENUS ARGULUS MEEHEAN 



503 



the mesial side (fig. 37, h). The females measure up to 8 mm. and 

 the males to about half that size. The host is the "Italrirana" in 

 Brazil. It is a fresh-water species. 



Thiele (1904) showed a pair of spinous prominences on the ante- 

 rior surface of the basis on the third swimming appendage. The 

 specimens at hand have one prominent one on the dorsal side of this 

 appendage, with the rest of the anterior appendage rounded to fit 

 under the lobe or pad projecting from the posterior surface of the 

 second appendage. 



Figure 37. — Argulus salminei: a. Accessory organs of last three legs of male ; b, respiratory 

 areas ; c, ribs of suction cups. 



On the dorsal side the base of the coxa projects posteriorly as a 

 rounded prominence, so that from a ventral view the tip appears as 

 a spinous pad median to the rounded voluminous swelling enclosing 

 the socket. The opening of the socket is an oblong slit, which is very 

 long to correspond to the size of the large pad. 



Two specimens labeled A. nattereri (Heller), No. 1261-91/435, are 

 identical with A. paulensis Wilson. The largest of these was 10.4 mm. 

 long. They do not fit Thiele's description of the type for nattereri 

 in two particulars — the anterior protuberance on the first antenna is 

 a knob rather than a hook, and the teeth on the basal plate of the 

 maxillae are short and broadly rounded rather than long and slender. 



Both groups of specimens seem to fit the description of A. salminei 

 Kr0yer. as given by Thiele, in every detail except one. He says that 

 there are about seven segments in the ribs of the suction cups. The 

 two groups in the Museum have about 16, and 9 or 10, respectively. 

 Since these divisions are somewhat dependent upon the size of the 

 animal and are the same in shape, the number of segments is not 

 significant. The male accessory appendages of paulensis and sahninei 

 are alike. The former therefore becomes synonymous with the latter, 



