NO. 2063. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 623 



arranged in 6 or 7 longitudinal rows, about 15 eggs in a row. First 

 antennae very short, not even reaching the end of the mouth-tube, 

 with no signs of segmentation and with two minute terminal spines. 

 Second antennae short and plump, not turned across the frontal 

 margin, but inclined inward, the exopod considerably smaller than 

 the endopod, two-jointed, and tipped with a pair of curved spines; 

 the endopod one-jointed and with three or four small processes rather 

 than spines toward the tip. 



First maxillae short and plump, tipped with three setae of unequal 

 size and without a palp; second maxillae slender, about the same 

 length as the trunk, and united to a small and button-shaped bulla. 

 These maxillae are fastened to the sides of the head much farther 

 forward than in any other species, their anterior margins actually 

 reaching the base of the second antennae. 



Maxillipeds with a stout basal joint and a short and curved term- 

 inal claw; the basal joint has a small projection on its inner surface, 

 and on the umer margin of the terminal claw is a comblike process, 

 somewhat similar to that in yimelodi. 



Color (preserved material), a uniform yellowish- white. 



Total length (without egg strings), 4 mm. Length of cephalo- 

 thorax, 1.75 mm.; of second maxillae, 3 mm.; of egg strings, 2 mm. 

 Width of cephalothorax, 1 mm. ; of egg strings, 0.55 mm. 



(lacae, from Kr0yer's specific name for the host). 



IfaZe.^Unkno wn . 



Remarks. — Kr0yer gives us very few details with reference to the 

 appendages of this species, and he regarded the description which 

 he gave as entirel}^ provisional. On the other hand, he was entirely 

 satisfied that the species was a valid one, and with the additional 

 details here given we may regard this as established. The species 

 agrees so closely with pimelodi and percarum that diagnostic separa- 

 tion seems at first difficult, but the present species may be recog- 

 nized by the great size of the abdomen and by the fact that the 

 second maxillae are attached so far forward on the sides of the head. 

 It is also significant that the abdomen, although so large, shows no 

 traces of segmentation 



The species is evidently a rare one, and it would be particularly 

 interesting to ascertain whether it mfests this host when in the salt 

 water. 



ACHTHERES COREGONI (S. I. Smith). 



Plate 36, figg. 75 to 80. 



Lernaeopoda coregoni Smith, 1874, p. 664, pi. 3, fig. 17. — Kellicott, 1880, p. 55, pi. 

 2, figs. 4 and 5. 



Host and record of specimens. — Smith's original description was 

 made from specimens found by J. W. Milner on the whitefish, Corego- 

 nus clupeiformis (C. alius Smith), at Ecorse, Michigan, and at Outer 



