66 U.S. NATIONAL MUSEUM BULLETIN 2 36 



basis. Setae on the endopodite number 3 on the 1st segment, 4 and 

 2 external on the 2nd, and 3 and 1 external on the apical segment, 



1st leg (fig. 18a) with seta on anterior aspect of coxa. Basis with 

 external seta and internal spine. Exopodites and endopodites 3- 

 segmented. Exopodal segments 1 and 2 with external spine, that 

 on 1st of great length. 3rd exopodal segment VA times as long as 

 2nd, with 3 spines at external margin, placed close together on distal 

 part of segment. Big apical spine and fine internal (almost apical) 

 seta. Endopodal segments 1 and 2 each with internal seta. On the 

 3rd endopodal segment there are 5 appendages in all: 2 internal (1 

 spiniform, 1 setiform), 1 apical, and 2 external. Exopodites and 

 endopodites of almost same length. 



The details of legs 2 to 4 can best be taken from figures 18b-d and the 

 setal formula. The endopodite of leg 2 is modified. Setal formula: 



endopodite exopodite 



leg 2 1.1.122 0.1.222 



leg 3 1.1.121 0.1.121 



leg 4 1.0.121 0.1.121 



Leg 2 (fig. 186) with particularly well-developed spine at apex of 

 1st endopodal segment. This spine reaches the apex of the ciu-iously 

 flattened 2nd endopodal segment. External border of 2nd endopodal 

 segment of legs 3 and 4 spiniformly produced. Apical exopodal 

 spines of legs 3 and 4 of considerable length. 



Leg 5 (fig. 18e) very small, represented by small, produced part of 

 distal ventral wall of 5th thoracic somite, bearing 4 setae. Genital 

 area on 1st abdominal somite strongly chitinized and stained too 

 heavily in my preparation, with the result that I cannot give a figure; 

 the big genital plates covering the apertures each have 2 setae. 



Color a light horny yellow, probably strongly faded in alcohol. 

 Antennules slightly darker. No eye or pigmented spots visible. 



Remarks. — A single specimen of this curious form occmTed in a 

 washing of the alga Lyngbya from the lagoon shelf of Falarik Islet in 

 the Ifaluk Atoll at a depth of about 6 feet. 



