no. 2354. NEW SPECIES OF PARASITIC COPEPODS— WILSON. 13 



We conclude, therefore, that this parasite belongs to the group of 

 Notodelphyoida, but that it can not be located in any of the exist- 

 ing families of that group. 



PSEUDOMOLGUS UAWAIIENSIS, new species. 



Plate 4, figs. 35-38 ; plate 5, figs. 44-48 ; plate 6, figs. 49-57. 



Host and record of specimens. — Eight females and three males were 

 obtained by the Bureau of Fisheries steamer Albatross at station 

 3853 during the Hawaiian explorations of 1902. They were ecto- 

 parasitic upon a large Tectibranch mollusk belonging to the genus 

 Pleuro b ranc hus. 



One of the females has been selected as the species type and has 

 been given Cat. No. 53564, U.S.N.M. The other females and the 

 males become paratypes with Cat. No. 53565, U.S.N.M. 



Specific characters of female. — Body rather slender, the cephalotho- 

 rax much wider than the genital segment and abdomen, and oval in 

 outline. The first thorax segment is the widest part of the body and 

 is distinctly separated from the head both by a dorsal groove and 

 by marginal notches. The second segment is nearly as wide as the 

 first ; the third and fourth segments are considerably narrower, while 

 the fifth segment is abruptly reduced to less than two-fifths the 

 width of the fourth segment. 



Genital segment barrel-shaped, the same length and width, Avith 

 the vulvae near the center of each lateral margin. Abdomen a little 

 more than half the width and about the same length as the genital 

 segment, three- jointed; joints the same width and length. Anal 

 laminae oblong, each tipped with four setae, two long ones in the 

 center and a short one on either corner. The egg strings are a little 

 less than half the length of the body, are narrowed anteriorly and 

 rather bluntly rounded posteriorly; eggs minute, about 400 in each 

 string. 



First antennae slender, a little longer than the cephalon and con- 

 taining seven distinct joints, the second much longer than any of 

 the others, and all except the basal joint moderately armed with 

 setae. Second antennae much shorter and stouter, four-jointed, the 

 last two joints fused and tipped with three claws of unequal length, 

 jointed near their tip. First maxillae with the mosticatory part 

 bifid, the two lappets long, lashlike, and incurved. These lappets 

 are also denticulate along their outer margin, the two proximal den- 

 ticles on the principal lappet being much larger than the others. 

 The palp is an irregular short lamella, armed with two tiny setae. 



Second maxillae with the terminal process armed with nine stout 

 spines of about equal length along the outer margin. Maxillipeds 



