NO. £063. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 691 



seta; second maxillae so reduced as to leave the bulla on the surface 

 of the trunk; maxillipeds with a stout basal joint, provided with 

 powerful muscles and armed along its imier margin with several 

 knobs and processes, irregularly arranged, and against which the 

 terminal claw shuts; the latter is large and stout, with an accessory- 

 claw on the inner margin near the tip and behind it a row of short 

 saw teeth. 



Color (preserved material), grayish -yellow, egg strings orange. 



Cephalo thorax, 5 mm. long, 1.25 mm. wide. Trunk, 3.2 mm. long, 

 4 mm. wide. Egg strings, 6 mm. long. 



Specific characters of Tnale. — Body completely folded together and 

 fused, so that all the appendages and the genital process are crowded 

 along the frontal margin; general form an eUipsoid, flattened laterally 

 and truncated anteriorly, with an even curvature and a smooth sur- 

 face; no dorsal carapace, but a short central rostrum projecting over 

 the mouth tube. 



First antennae four-jointed, the basal joint much larger than the 

 others; second antennae biramose, the exopod two-jointed and tipped 

 with a tuft of short setae, the endopod smooth except for a single spine 

 on the outer margin; first maxillae similar to those of the female; 

 second maxillae large and stout, with a long and powerful terminal 

 claw; maxillipeds shorter but just as strong. 



The internal anatomy of this male is shown in figure 198 and may 

 be described as follows: The esophagus (oe) is slender and nearly 

 straight; its dorsal wall is only a single cell in tliickness, while in the 

 ventral wall two rows of nuclei may be seen, and there is a corre- 

 sponding increase in thickness. The stomach (s) Hes close to the 

 dorsal surface and is abruptly and considerably enlarged at the 

 anterior end. It passes insensibly into the intestine, wliich curves 

 around the posterior part of the trunk, still close to the dorsal 

 surface, and ends bhndly at the point e. The frontal secretory 

 gland (fg) is very similar to that in AcJitheres, and fills the entire 

 front of the head above the esophagus. The median center of 

 the maxilhpedal gland (mp) may be seen between the dorsal 

 surface of the stomach and the adjacent body wall; the lateral 

 centers appear in other sections. These excretory glands are much 

 reduced in such dwarfed males, and although the centers are fairly 

 distinct the ducts can not be discerned. There is about the same 

 difference between the infra- and supra-esophageal gangha as was 

 found in Achtheres. The supra ganghon {sg) is oval in section and 

 sends out a good-sized nerve to the frontal margin. Another nerve 

 extends from the posterior end to the frontal gland, the anterior end 

 of the stomach, and the median center of the maxilhpedal gland. 

 The infra gangUon iig) is much larger and very irregular in outhne, 

 and supplies the lower lip, the various mouth-parts, and the repro- 



