70 U.S. NATIONAL MUSEUM BULLETIN 236 



Ventrally the genital somite has the aspect illustrated in figure 196. 

 The genital field occupies a minor portion of the somite and is charac- 

 terized mainly by the presence of small genital opercula, visible as a 

 bUobated structure on the ventral surface. The distal ventral wall of 

 the somite is produced into two flaps, bordered by exceedingly fine 

 spinules. 



Antennules (fig. 20/) very short, K length of cephalic somite, 3rd 

 segment with small conical process bearing short aesthetasc and 2 fine 

 setae. The antenna and mouth parts have not been studied in detail. 



Legs 1 to 4 have 3-segmented exopodites and endopodites; the details 

 can best be taken from figures 20a-d and from the setal formula: 



Leg 5 with distinct knob halfway along internal border of exopodite. 

 Baso-endopodite reaches slightly beyond middle of exopodite. Exop- 

 odite with 4 spiniform setae; 1 and 4 have almost same length, seta 

 2 is longer, seta 3 much finer and short. Baso-endopodite with 2 

 setae, internal as long as 1 or 4 of exopodite; external seta short, 

 dagger-shaped (fig. 20e). 



Adult male, total length 0.36 mm,; length of longest furcal seta 

 0.18 mm. 



General shape of body as in female, i.e., spindle-shaped in dorsal 

 aspect, with greatest diameter at end of thoracic somite. Anterior 

 part rounded, front with rostral base distinctly visible, posteriorly 

 gradually tapering, no sharp demarcation between thorax and abdo- 

 men. Head and 1st thoracic somite completely fused to form cephalic 

 somite, which is as long as combined lengths of thoracic somites 2 and 4. 

 At the end of the cephalic somite there is the same row of threadlike 

 spinules, some distance from the border. 5th thoracic somite rather 

 small in dorsal aspect but distinctly visible in lateral view; 1st and 2nd 

 abdominal somites separate (fig. 21a). A small spermatophore is 

 visible in the 1st abdominal somite. Abdominal somites 1 to 4 have 

 nearly the same length, distal borders smooth, without hairs or 

 spinules. Anal somite short; anal flap distinctly rounded, clearly 

 visible. Fiu-cal rami as in the female; development of the setae also 

 identical. 



The ventral aspect of the genital somite is of characteristic appear- 

 ance: the genital operculum is a very prominent feature, forming a 

 squarish lobe, provided on each side with two powerful setae. The 

 median seta almost reaches the aiticulation between abdominal 

 somites 2 and 3; the external seta is much longer and reaches the anal 



