176 U.S. NATIONAL MUSEUM BULLETIN 236 



Adult female, total length 0.44 mm.; greatest diameter 0.18 mm.; 

 length of longest furcal seta 0.39 mm. Proportional length of cephalo- 

 thorax and abdomen is 17:12. 



Body robust, especially in dorsal aspect; cephalothorax ovoid, 

 greatest diameter in region of oral appendages, sharply set off from 

 abdomen (fig. 64a). Head and 1st thoracic somite completely fused 

 to form cephalic somite, slightly longer than combined lengths of 

 thoracic somites 2 to 4. Back, in lateral aspect, rounded, very grad- 

 ually continuing into rostrum (fig. 646). Rostrum strong, curved, 

 triangular with blunt apex, pointing forward and slightly downward, 

 equal in length to combined lengths of antennular segments 1 to 3. 

 Rostral base visible in dorsal view as rounded eminence in front of 

 cephalic somite, separated by very weak groove. Cephalic somite 

 laterally produced to cover basal parts of oral appendages, latero- 

 distal corner rounded. Thoracic somites 2 and 3 of same length, 

 4th somite slightly longer. All 3 somites with well-developed 

 epimeral plates, cut off squarely in lateral aspect. 



5th thoracic somite small, very visible in lateral aspect, slightly 

 visible in dorsal aspect, as narrow band. Genital somite, resulting 

 from fusion of somites 1 and 2, very prominent feature of abdomen, 

 as long as rest of abdomen, furca included. Genital somite cylindrical, 

 with distinct line of fusion, no spinules (fig. 64a). 3rd and 4th abdom- 

 inal somites of equal length, strongly telescoped, nude. Anal somite 

 well developed, with broad anal plate, deeply incised between inser- 

 tion of furca. Two rows of fine spinules occur on each side of anal 

 somite near insertion of furcal rami. Furcal rami slightly wider 

 than long (proportion 4:3), with appendicular seta and 5 marginal 

 setae on each ramus. Setae 1, 5, and appendicular seta short, 5th 

 spiniform, 4th slightly longer. Setae 2 and 3 lengthened, especially 

 2nd which reaches about body length. 



Antennules short, 7-segmented, 4th segment twice as long as broad, 

 with fairly long tubercle carrying aesthetasc and 2 setae. During 

 preparation, the appendage fragmentated, with the result that I 

 could not figure the setation. Setae on basal 3 segments short and 

 plumose; on apical segments long and apparently nude. 



Antenna (fig. 65^) with small, 3-segmented exopodite, number of 

 setae 2, 1, and 3, respectively. AUobasis with 1 internal seta. 

 Endopodite with 7 terminal setae and 2 lateral spines. Of apical 

 setae, 4 are geniculate, 2 are straight, and 1 is short, compressed and 

 dagger-shaped. 



Mandibular praecoxa well developed, with strong cutting edge 

 bearing 5 blunt, strong teeth and long basal seta. Exopodite small, 

 2-segmented, with 1 and 4 setae respectively. Endopodite small, 

 segmentation indistinct, with total of 5 setae (fig. 65h). 



