NO. J573. PARASITIC COPEPODS— WILSON. 399 



Posterior lobes broad, bluntly rounded, and exceptionally long, 

 reaching back neariy to the fourth thorax segment; posterior margin 

 between the lobes nearly straight; accessory lobes small, semi- 

 elliptical, wider than long. Eyes close together and in approximately 

 the same position as in the female. Three free thorax segments of 

 about the same length, but the first one-half as wide again as the 

 other two, which are nearly equal. 



Lateral appendages of the second segment wide, divergent, bluntly 

 rounded at the tip and reaching beyond the posterior margin of the 

 third segment. Each is reenforced on its inner margin with a wide, 

 transparent, membranous flap. Tliird and fourth segments the same 

 width as the genital segment, with evenly rounded sides, and without 

 lateral appendages. 



Genital segment subquadrate, the sides slightly convex, the poste- 

 rior angles prolonged a little into small rounded lobes, with a second 

 pair ot small lobes just in front of them on the lateral margins; both 

 pairs of lobes are armed on their ventral surface with small spines. 



Abdomen two-jointed, joints the same width, but the basal one 

 not more than half the length of the terminal; the latter has its 

 posterior angles obliquely truncated and the anal incision is deep 

 and triangular. Anal laminae large, a trifle longer than wide, the 

 posterior margins nearly straight and armed with four large plumose 

 setae, evenly graded in length, the outer ones the longest. Joints of 

 the first antennae the same length, setae longer than in the female; 

 terminal claw of the second antennae also much longer and more 

 slender, but the claw is bent similarly at a sharp angle near the tip. 



First maxillipeds the counterpart of those of the female, except 

 that the outer terminal claw is one-third shorter than the inner; 

 second pair ver}^ large and swollen, the movable finger of the forceps 

 jaws developed into a long curved claw, the stationary one a rounded 

 knob. All the swimixdng legs biramose, the rami two-jointed, with 

 the spines and setae arranged as follows: First exopod, 1, 0; 4, III: 

 endopod, 0, 0; 0, III: second exopod, 1, I; 3, VI: endopod, 0, I; 

 0, VI: tlurd exopod, 0, I; 3, VI: endopod, 0, I; 0, VI: fourth exo- 

 pod, 1,1; 0, VI: endopod, 1,1; 0, IV. 



Total length, 7.5 mm.; length of carapace on mid-line, 3 mm.; 

 width of same, 3.85 mm.; length of three free segments, 2.13 mm,; 

 length of genital segment, 1.66 mm. 



Color of both sexes (preserved material) a yellowish brown, darker 

 along the nud-line, ^^dthout pigment markings. 



(brevicaudis, hrevis, short, and cauda, tail.) 



The U. S. National Museum Collection contains a male of this 

 species with the following label: '' Nogagus validus (Dana), No. 6822, 

 on Carcharias between Papua and Japan, G. S. Brady, England, 

 Ace. No. 14181, Exchange.'' This therefore is not one of Dana's 

 original specimens, but was taken on the Challenger expedition and 



