No. 2194. NORTH AMERICAN PARASITIC COPEPODS— WILSON. 87 



Total length, if the body were straightened, about 40 mm. Great- 

 est diameter of trunk, 8 to 10 mm. Length of egg strings if 

 straightened, 150 to 200 mm. 



{hranchialis^ pertaining to the gills, which are its habitat.) 



Internal syecif-o characters of female. — Esophagus short and in- 

 clined at an angle of about G0° to the axis of the neck, entering 

 the stomach at the anterior end with little or no sphincter muscle 

 at the junction. 



Stomach increased to about 2 diameters in the neck, passing insen- 

 sibly into the intestine, which is abruptly enlarged in the genital 

 segment. 



The fused ovaries are produced into horn-like projections anteri- 

 orly and posteriorly, which are strongly flattened dorsoventrally and 

 fit down on the dorsal surface of the intestine like a saddle, the flaps 

 extending nearly to the center of the side of the intestine. Each an- 

 terior horn tapers to an apex which lies dorsal to the intestine and 

 from which the oviduct leads around the outside of the intestine to 

 the ventral surface and follows that surface back to the vulva. These 

 oviducts are exceptionally narrow compared with the size of the 

 parasite and along the ventral surface are wholly ventral to the in- 

 testine. Each cement gland is about the same diameter as the oviduct, 

 along whose inner ventral surface it extends, the two glands being 

 in contact with the ventral body wall and close to the midline. The 

 anterior end of the gland turns up with the oviduct for a short dis- 

 tance on the outside of the intestine at the base of the neck and termi- 

 nates in a blunt point. The chitinogen layer of the body wall is 

 poorly developed. 



Specific characters of the Copepodicl male. — Cephalothorax ellip- 

 tical, narrow anteriorly through the bases of the antennae, almost 

 squarely truncated posteriorly, and covered with a dorsal carapace. 

 Second, third, and fourth thorax segments about the same length and 

 width, which latter is half that of the carapace. Line of demarka- 

 tion between the fifth and genital segments indicated by lateral 

 notches. Abdomen short, much narrower than the genital segment; 

 anal laminae each armed with 4 or 5 setae. First antennae four- 

 jointed, the basal joint much longer than any of the others, each 

 joint well armed with setae; second antennae comparatively small, 

 two-jointed, the joints about the same size and triangular, the termi- 

 nal joints tipped with a stout chela. Proboscis long and fairly stout; 

 mandible in the form of a long and slender spine; first maxilla a 

 short papilla tipped with two long setae; second maxilla two-jointed, 

 joints the same width but the basal one somewhat the longer, termi- 

 nal claw short and stout; two-jointed maxillipeds present behind the 

 maxillae, the terminal joint the same length as the basal but much 

 narrower, terminal claw short and pointed. 



