536 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 94 



the female, the t^Yo abdominal segments and the caudal rami are 

 more or less completely fused. 



The antennae, mouth parts, and swimming legs are like those of 

 the female except for the fourth legs. These are stout and the 

 three terminal segments combined are longer than the basal segment. 

 The spine at the distal corner of the second segment is short and 

 strongly curved and the three terminal spines are very unequal in 

 length. Total length, G mm. Carapace, 3.6G mm. long, 3.15 mm. wide. 



Remarks. — The presence of lobes at the posterior corners of the 

 genital segment in the female and the more or less complete fusion 

 of the two abdominal segments with each other and with the caudal 

 rami in both sexes are the best characters for identification. 



LEPEOPHTHEIRUS MARCEPES,^ new species 



Plate 33, Figukes 192-195 



Forty specimens, all females, were taken by Dr. Waldo L. Schmitt 

 from the gills and under surface of a lemon sole {Pleuronectes quad- 

 rituberculatus) caught in Alitak Bay, Kodiak Island, Alaska. One, 

 U.S.N.M. No. 79G87, has been selected to serve as the type of this 

 new species. 



Female. — Carapace elliptical, 10 percent longer than wide, the 

 lateral lobes narrowly rounded and not reaching the posterior margin 

 of the median lobe. Front of the carapace broad and flattened, 

 with a median incision. Fourth segment one-third as wide as the 

 carapace, its sides strongly convex. Genital segment longer and wider 

 than the carapace, narrowed anteriorly to the width of the fourth 

 segment, the posterior corners broadly rounded and the posterior 

 margin concave. Abdomen longer than the genital segment but only 

 a fourth as wide and 2-segmented, the proximal segment 12 times as 

 long as the anal with parallel sides. 



The antennae and mouth parts are of the usual type for this genus, 

 without specific characters. The first legs are short and rather stout, 

 the end segment with three terminal claws diminishing in size back- 

 ward and three large plumose setae on the posterior margin. The 

 second and third legs are of the typical biramose form, but the fourth 

 legs are very exceptional for this genus. Although the adult female 

 averages 6 mm. in length these fourth legs are only 0.16 mm. long 

 and easily escape any but the most careful examination. When suf- 

 ficiently magnified, however, they are revealed as 3-segmented, the 

 basal segment with a seta at the anterior distal corner, the second seg- 

 ment diagonal with a stout spine at its outer corner, and the third seg- 

 ment w^ith two very uneciual terminal spines. The egg strings are 



' From marceOj to shrink or shrivel. 



