NO. 1788. NORTH AMERICAN EROASILID^— WILSON. 363 



without tooth or branch, but is armed with two huge plumose setae, 

 which are attached to the outer curve close to the base of the claw. 



First swimming legs with a one-jointed exopod and a three-jointed 

 endopod. The former is armed with five plumose setse; the two 

 basal joints of the latter each carry one seta on their inner margin, the 

 terminal joint carries five. The arrangement of the spines and setas 

 on the second, third, and fourth legs is as follows: Second exopod, 

 I-l; II-l; III-5: endopod, 0-1; 0-2; II-3: third exopod, I-O; 

 I-l; II-5: endopod, 0-1; 0-2; III-2: fourth exopod, I-O; I-l; 

 11-5: endopod, 0-0; 0-0; II-l. 



The arrangement of the spines and setse as well as the contour of 

 the leg itself makes it reasonably certain that the last joints of the 

 exopods of these three pairs of legs is really a fusion of two jomts, but 

 there are no signs of any groove between them. The claws have the 

 structure shown in figure 137, and are thus peculiar. 



Total length, 2 mm. Cephalothorax 0.8 mm. long, 1 mm, wide. 

 Length of second, third, and fourth segments, 0.75 mm. Length of 

 egg-strings, 0.75 mm. Length of inner seta on the anal laminae, 0.6 

 mm. 



Color a rich seal brown, uniform over the entire dorsal surface, 

 lighter and somewhat yellowish on the ventral surface. 



{ssetiger, armed with setae, alludmg to the large ones on the max- 

 illipeds). 



The National Museum collection contains a single lot of this species, 

 consisting of three females taken from the fl3nng fish, Exoccetus 

 volitans, at Woods Hole, Massachusetts, which is numbered 38629, 

 U.S.N. M. These are made the types of the new species. 



ARTACCLAX ARDEOL^ (Kroyer). 



Plate 52; Plate 53, fig. 147. 



Bomolochus ardeolse, Kroyer, 1863, p. 220, pi. 11, fig. 3, a to e. 

 Artacolax ardeolx, Wilson, 1908, p. 434. 



Female. — Body tadpole-shaped, the cephalothorax more than four 

 times the width of the posterior portion. Cephalothorax semi- 

 elliptical in shape and almost twice as wide as long, the anterior 

 margin evenly rounded, the posterior margin a straight line. Second 

 (first free) segment considerably narrower than the carapace and 

 tapered posteriorly; third and fourth segments rigidly fused, one- 

 third narrower than the second segment, and together about equaling 

 it in length. Fifth segment abruptly narrowed to one-third the 

 width of the fused segments, and distinctly separated from the 

 genital segment, its lateral margins slightly concave. Genital seg- 

 ment the same width anteriorly as the fifth segment, but somewhat 

 narrowed posteriorly, the same length as the second segment and 

 barrel shaped, with nearly straight sides. 



