490 PROCEEDINGS OF THE NATIONAL MUSEUM vol.88 



behind the eyes and diverging ahead of them. Respiratory areas well 

 separated, almost equal in size and shape (fig. 29, a). 



First antennae with an anterior hook; ventral mesial spine fairly 

 large, basal spine of first antennae very large, spine on second antenna 

 long and broad and postantennal spine very broad. These differ from 

 fugettensis in that the spines at the base of the first antennae and 

 near the midline are so very broad and the anterior hook is placed so 

 far laterally on the lateral hook. 



Suction cups about one-fifth the width of the carapace, with 18 or 19 

 imbricate plates in the ribs (fig. 29, 5). This is very similar to the 

 female pugettensis. Second maxillae slenderer and without so prom- 

 inent spinous pads, with three broad blunt teeth, median one slightly 

 broader than the other two, postmaxillary spines fairly long, both 

 pairs pointing medially. 



Swimming appendages without flagella. Second appendage with 

 broadly bilobed lamella on posterior ventral edge (fig. 29, c). Third 

 appendages with the dorsoanterior edge of coxa rounded proximally 

 and armed with spines, ventral distal edge with an upright fingerlike 

 papilla projecting anteriorly and a rounded papilla dorsal to it (fig. 

 29, d) . On the fourth appendage there is a small rounded lamella on 

 the posterior surface of the basis and a more broadly rounded blade- 

 like lamella on the posterior surface of the coxa. The usual chitinous 

 ridge extends obliquely across the basal segment with the peg orig- 

 inating on the dorsal distal end of the last basal segment and curved 

 medially above this basal part like a curved finger (fig. 29, e). 



There seems to be no indication of the socket from the ventral side 

 of the animal, but on the dorsal side of the third appendage it may be 

 seen as a saddled-shaped depression on the distal end of the basis, 

 while the two rami are fused at their point of origin to form a broad 

 base. This armature, the absence of flagella on the swimming ap- 

 pendages, and the two very nearly equal respiratory areas are all 

 different from those of pugettensis. 



ARGULUS BOREALIS Wilson 



Figure 30 

 Argulus horealis Wilson, 1912a, p. 85, pi. 3. 



Carapace slightly longer than wide, ovate ; cephalic area prominent, 

 eyes fairly large, alae reaching third appendages in female, fourth 

 appendages in male. Abdomen elliptical; anal sinus shallow; anal 

 furcae basal, tips diverging, testes extending almost full length of 

 abdomen. Color almost lacking in the body except a brown band 

 extending posteriorly from the edge of the cephalic areas paralleling 

 the edge of the alae; dorsal surface of abdomen somewhat rusty in 

 female; brown color on each side of testes in male. The respiratory 



