AET. 17. AMERICAN PARASITIC COPEPODS — WILSON. 5 



small, placed far forward, well separated, and very weakly pig- 

 mented. Sucking disks large, and placed well forward, each one-fifth 

 as wide as the carapace. The ribs which support their free margins 

 are slender, straight, tapering, and about 12- jointed. The maxillipeds 

 are stout, the basal joint armed with three bluntly truncated laminae 

 on its posterior margin; the ventral surface of the second and third 

 joints is covered with small corrugations which do not quite touch 

 one another. The first and second legs are well covered by the 

 carapace, the third and fourth pairs are entirely visible in dorsal 

 view. The lobes on the basal joints of the fourth pair are narrow- 

 conical and about half the length of the second joint. The first two 

 pairs are furnished with large flagella, but there are none on the last 

 two pairs; these are specially prominent on the older female. 



Color. — (Preserved material) a plain grayish white, the eggs show- 

 ing through as a distinct orange-yellow; eyes almost invisible but 

 with a faint wash of reddish-brown. 



Total length 6 mm. Carapace 4.50. mm. long, 4.80 mm. wide. 

 Abdomen 1 mm. long, 0.80 mm. wide. The larger female measures 

 8.50 mm. in total length and the carapace is 7.50 mm. wide. 



{paidensis, from Sao Paulo, Brazil.) 



/Specific characters of the male. — The male is smaller than the 

 female but otherwise quite similar. Carapace wider than long and 

 not reaching the anterior margins of the third legs. Abdomen rela- 

 tively larger than in the female and nearly as wide as long. Eyes 

 larger, farther forward, and closer together than in the female. Of 

 the supplementary sexual characters the peg on the second joint of 

 the fourth legs is large and long and extends diagonally outward. 

 There is a small protuberance on the posterior margin of the basal 

 joint of the third legs, and a wide flap or lamina on the posterior 

 margin of the second joint. The second legs have a long and narrow 

 flattened projection on the posterior margin of the second joint. 



Color. — Similar to that of the female. 



Total length 5.50 mm. Carapace 3.85 mm. long, 4 mm. wide. 

 Abdomen 1.08 mm. long, 1 mm. wide. 



Remarks. — This is another of the fresh-water argulids of South 

 America, and may be distinguished from Kr0yer's salminei as 

 follows : 



Kr0yer said of his species, " Color a pleasing liver-brown, with a 

 narrow dark margin anteriorly on the upper surface of the carapace 

 and a small dark spot at the base of the incision of the tail (genital 

 segment) . The grooves which separate the cephalic from the lateral 

 areas are darker and more yellow in color than the rest of the dorsal 

 integument. Eyes black * * *. Jxi the male the dark border of 

 the carapace and the small black spot at the base of the anal sinus 



