NO. 19 NEW PARASITIC COPEPODS — WILSON 3 



The male. — Carapace more than half the entire length and a little 

 longer than wide, narrowed anteriorly less than in the female. Fron- 

 tal margin with no trace of a median depression or incision ; posterior 

 sinuses small and shallow. Median lobe more than half the width of 

 the carapace and projecting considerably behind the lateral lobes, with 

 an evenly rounded posterior margin. Free segment short, its lateral 

 margins scarcely projecting at all for the attachment of the fourth 

 legs. Genital segment narrow, not much wider than the free segment 

 and almost twice as long as wide, without any trace of posterior lobes. 

 Abdomen two-segmented, the distal segment twice as long as the 

 proximal, both segments of the same width, which is half that of the 

 genital segment. Caudal rami longer than wide, enlarged posteriorly 

 and each armed with five setae, three of which are three times the 

 length of the ramus while the other two are much shorter. 



Appendages like those of the female, but the terminal claw of the 

 second antenna has two spines on its inner margin and that of the 

 maxilliped has one spine on the inner margin near the base. The 

 fourth swimming legs nearly reach the posterior margin of the geni- 

 tal segment and their armature is like that in the female. 



Total length 4.2 mm. Carapace 2.3 mm long, 1.9 mm wide. 



Remarks. — The posterior lobes of the genital segment in the female 

 are exceptionally long and wide, and the specific name alludes to this. 

 When taken in connection with the two abdominal segments of equal 

 length, they furnish a quick identification of the species. The identity 

 can then be confirmed by the structure of the second antennae, the 

 furca, and the first and fourth swimming legs. 



NESIPPUS CRYPTURUS Heller, new male 



Plate I, figs. II, 13, 14; plate 3, figs. 28-32 



Occurrence. — More than 60 females were taken from the gills and 

 throats of two large sharks, and nearly as many males from the outer 

 skin and fins of the same hosts. The females were described 70 years 

 ago by Heller but these are the first males to be found. Males, 

 U.S.N.M. no. 64057 ; females, U.S.N.M. no. 64058. 



The male (fig. 28). — Width of the cephalothorax one-half greater 

 than its length on the midline ; frontal plates distinct but rather nar- 

 row; posterior lobes broadly rounded and short, not reaching the 

 center of the lobes of the second segment. Second, third, and fourth 

 segments the same length but diminishing considerably in width. 

 Second segment with well-rounded lateral lobes reaching almost to 

 the posterior margin of the third segment, fourth segment much 



