COPEPODS OF THE WOODS HOLE EEGION 383 



its surface is roughened by the usual rows of spines, and from near 

 the outer distal corner projects a peculiar foot-shaped process, with 

 a prominent heel and two stout setae for toes. The distal segment 

 terminates in five curved claws of varying lengths and a large 

 rounded process covered with spines. 



The mandibles are slender, turned back beneath the upper lip, and 

 tipped with a short and slender spine, minutely denticulate along 

 each lateral margin. The three setae of each first maxilla vary 

 greatly in size, the inner one being three times the length of the 

 outer, while the middle one is halfway between the other two. Tlie 

 basal segment of the second maxilla is stout and inclined backward; 

 the second segment is comparatively small and is terminated by two 

 blunt spines, about the same length and minutely denticulate along 

 their anterior margin. The maxillipeds have a slender basal seg- 

 ment, carrying on its inner margin a short and blunt papilla, tipped 

 with a tuft of short cilia. The terminal claw is very long and 

 slender and is bent into the shape of the letter S, with a short and 

 weak plumose seta on the ventral surface at the base. 



The first legs are moderately widened, each ramus 3-segmented, 

 its terminal segment armed with five flattened plumose setae. The 

 three following pairs of legs have 3-segmented rami, the endopods 

 of the third and fourth pairs quite slender, with elongate terminal 

 segments. The fifth legs are uniramose and 3-segmented, the ter- 

 minal segment longer than the two basal segments combined, and 

 armed distally with four unequal nonplumose setae. Total length, 

 1.8-2.1 mm. 



Male. — Unknown. 



Remarks. — This species can be identified by the enlarged third 

 segment of the second antenna, with its foot-shaped process, and by 

 the papilla on the inner margin of the basal segment of the maxilli- 

 peds. When alive these copepods are very active and move about 

 over the inner surface of the pocket with ease and rapidity. They 

 are easy to find since their white color stands out in contrast to that 

 of the fish's skin. Extensive search has failed to reveal a single 

 male. 



Genus ARTACOLAX Wilson, 1908 



Head fused with the first segment and much wider than long; 

 second segment free, third and fourth segments fused and overlap- 

 ping the fifth segment dorsally ; fifth segment free and abruptly nar- 

 rowed to half the width of the fused third and fourth segments, or 

 less. Urosome 4-segmented in the female, 3-segmented in the only 

 known male ; genital segment enlarged but little ; caudal rami short. 

 First antennae 6-segmented; second antennae 3-segmented, with 

 stout apical claws; maxillipeds turned forward outside the other 



