NO. 2063. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 627 



The cement glands are relatively very wide, filling the whole of 

 the doi-so-lateral portions of the trunk (fig. 9). These and the 

 remaining portions of the internal anatomy of this species have already 

 been described under morphology (see p. 582, and following). 



Color, a uniform yellowish-white, without pigment except in the 

 egg strings, which become orange with maturity. 



Total length (excludmg egg strings), 4 mm. Length of cephalo- 

 thorax, 1.5 mm.; of trunk, 2.5 mm.; of egg strings, 2 mm.; of second 

 maxillae, 2 mm. Width of cephalo thorax, 1 mm.; of trunk, 1.85 mm. 



Specific characters of male. — Cephalo thorax considerably smaller 

 than the trunk, from which it is separated by a short waist; trunk 

 spindle-shaped and distinctly segmented, first or basal segment the 

 longest, the othere diminishing regularly, except that the fifth seg- 

 ment is longer than the fourth; no anal lammae; first antennae three- 

 jointed and tipped with two long setae; second pair biramose, the 

 endopod curved and one-jointed, the exopod two-jomted and tipped 

 with a claw; first maxillae relatively small, with two medium-sized 

 setae at the tip; second maxillae slender and three times the length of 

 the maxiUipeds, the basal joint much elongated and fairly stout, the 

 second joint short, and the termmal claw also short and slender; 

 maxillipeds short and stout, the basal joint swollen and armed on its 

 inner mai^in with a large process covered with spmes, against which 

 the short and stocky terminal claw shuts. 



Color, a pale yellowish-white. 



Total length, 1 mm. Greatest diameter, 0.3 mm. 



The larvae and developmental stages of this species have been fully 

 described in the ninth paper of the present aeries. 



(ambloplitis, the generic name of the host.) 



RemarTcs. — This species is as typically American as A. percarum is 

 European, and is fully as widely distributed. Owing to the habits of 

 its principal host, the red-eye, the specimens found on those fish are 

 likely to be themselves parasitized, either by some of the VorticeUidae 

 or by algae. Sometunes the body of the copepod is so completely 

 covered that it looks as if it were clothed in fur. At other times it 

 has, seemingly, long tufts of hair on its head or rump, or even on the 

 second maxiliae. 



The species may be recognized by its small size, relatively short 

 and spindle-shaped body, short and plump egg strings, the prominence 

 of the second antennae, and the pattern of the dorsal surface of the 

 head. As KeUicott observes, it lives chiefly on the mner surface of 

 the gill arches, which in the red-eye are covered with teeth. The 

 copepods, especially the younger and undeveloped stages, are so small 

 and so mmgled with the gill teeth as to be easily overlooked. But 

 careful examination of the gill arches of almost any red-eye will reveal 

 some of the parasites, and often many are found together on the same 

 fish. 



