NO. 2063. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 621 



presented by Dr. Tarleton H. Bean, State Fish Commissioner of 

 New York, No. 43566, U.S.N.M. The species was reported by 

 Wright in the paper above cited as "found in considerable numbers, 

 both male and female, in the mouth cavity and on the gill arches of 

 the small-mouthed black bass, Micropterus salmoides (Lac.) Gill," 

 in the vicinity of Toronto, Canada. 



Specific characters of female. — Head considerably smaller than 

 the trunk, the difference being about the same as m amhloplitis and 

 much greater than in corpulentus; dorsal carapace projecting but 

 little at the frontal margin, relatively wider anteriorly and narrower 

 posteriorly than m amhloplitis; trunk broadly ovate, narrowed into a 

 neck where it joms the cephalothorax and broadly rounded pos- 

 teriorly; abdomen relatively larger than in amhloplitis, wider at the 

 base where it sends out a romided lobe on either side on the dorsal 

 surface, and more distinctly segmented; egg strings the same width 

 as the abdomen, shorter than the trmik, and tapering toward their 

 tips ; eggs rather small, in 3 or 4 longitudmal rows, about 50 in each 

 string. 



First antennae attached some distance behmd the mouth, dis- 

 tinctly three-jointed, the basal jomt considerably the longest and 

 stoutest, the terminal joint armed with three good-sized setae. 



Dorsal ramus (endopod) of second antemia tipped with a row of 

 toothed and sickle-shaped spines; exopod distinctly jointed and end- 

 ing in a small claw. Mandible eight- or nine-toothed, the first tooth 

 bluntly rounded, the third tooth rudimentary and very short; inner 

 margin of the shank sharpened to a knife-edge, widest just behind 

 the teeth. First maxillae very broad and swollen through their 

 center, tipped with two setae, wiih a third one on the inner margin 

 which is curved strongly backward. 



Maxillipeds with a medium basal jomt, armed near the center of 

 the mner margin with a raised papilla covered with small spines; 

 the terminal claw is only slightly curved and carries on its inner 

 margin an accessory claw, behind which is a more or less prominent 

 serrated ridge. Second maxillae closely resembling those of amhlo- 

 plitis in length, diameter, and wrinkling; bulla saucer-shaped and not 

 fully chitinized. Spermatophores minute and spherical, sometimes 

 fastened with so much cement as to deform the abdomen. 



Color a decided yellowish-white, the yellow deepening to orange 

 through the center of the body as the eggs ripen in the convolutions 

 of the oviducts. 



Total length (exchiding egg strings), 4 to 4.5 mm. Length of 

 cephalothorax, 1.33 mm.; of trunk, 2.66 mm.; of egg strings, 2.25 

 mm. Width of cephalothorax, 1 mm. ; of trunk, 2 mm. 



Specific cliaracters of male. — Relatively much larger than in amhlo- 

 plitis, but having almost exactly the same shape and proportions. 



