NO. IJOl. PARASITIC COrEPODS—CALiaiD.E— WILSON. 565 



trapezium or wedge which .stands out A^ery prominently upon the 

 dorsal surface of the carapace, Furthermore, the transparent border 

 surrounding- the carapace, instead of being more broadly rounded 

 than the lateral lobe at the posterior extremity of the latter, the con- 

 dition which prevails in all other species, comes to a sharp point, 

 giving the carapace a peculiar angular appearance. 



The free thoracic segment is very short and narrow, a))out three- 

 fifths as wide as the genital segment. Genital segment oblong, with 

 well-rounded corners, half as wide as the carapace, with short and 

 blunt posterior lobes between which the posterior margin is concave. 

 Abdomen four-fifths as long as the genital segment and somewhat less 

 than half as wide; sharply contracted where it joins the genital seg- 

 ment and slightly swollen at the center. Anal papilhe large, well sep- 

 arated, and somewhat curved inward at the tips, bearing plumose 

 seta^ which are very long and slender. Egg cases three-quarters as 

 wide as the abdomen and a little longer than the carapace; about 60 

 eggs in each. Anterior antennje short and stout, the basal joint very 

 plentifully supplied with plumose seta' along its anterior and lateral 

 margins; terminal joint club-shaped. 



Second antenna with a stout basal joint reinforced by a short, l)lunt 

 spine posteriorly; terminal joint long and slender, with an abrupt 

 curve. First maxilhe short, blunt, almost straight, and considerably 

 swollen at the base. 



Second maxilhe simple, un))ranched, nearly as long as the rostrum, 

 slightly curved if at all, and acuminate. 



First maxillipeds with a stout l)asal joint and a long slender terminal 

 joint; the inner terminal claw twice the length of the outer; a short 

 si)ur on the inner margin of this joint near the distal end. Second 

 maxillipeds with a stout and swollen basal joint and a very weak and 

 slender terminal claw, the disproportion between the two being (juite 

 noticeable. 



The claw is only half the length and not more than one-fifth the 

 width of the basal joint, and its terminal portion beyond the base of 

 the accessory spine is scarcely larger than the spine itself. The inner 

 margin of the 1)asal joint is raised into a slight knob opposite the base 

 of the accessory spine, but the flimsy little terminal claw does not 

 look as though it could hold down very much against this knob. 

 Furca long and narrow, with ])ranches about the same length and width 

 as the basal portion; considerably narrowed at the center, like an hour- 

 glass. The divergent branches curve inward toward each other, while 

 the sides of the base curve outward away from each other, but only 

 slightly in either case. Often the branches are somewhat swollen at 

 the tips. 



The first legs are short and stout, w ith two spines on the posterior 

 border of the basal joint and a single small spine at the distal end of 



