64 U.S. NATIONAL MUSEUM BULLETIN 236 



nearly same length, each shorter than 2nd or 3rd. All thoracic somites 

 have normally developed, rounded epimeral plates. 



1st and 2nd abdominal somites comparatively long, of equal length; 

 3rd abdominal somite slightly shorter than 2nd; 4th abdominal somite 

 half length of 1st or 2nd abdominal somite. No spinules or hairs 

 along distal margins. 5th (anal) somite almost completely telescoped 

 into 4th; operculum small, nude. 



Rami of furca 4 times as long as wide, widely separated, slightly 

 diverging, each ramus with broad base, gradually tapering, external 

 border straight, internal border concave. There are 6 marginal setae 

 and 1 appendicular seta on each ramus. Seta 1 short and fine, placed 

 at internal furcal border, some distance from apex. Setae 4, 5, and 

 appendicular setae fine, slightly longer than seta 1. Setae 2 and 3 

 lengthened and thickened, especially 2nd, which surpasses length of 

 abdomen. Seta 6 small, at % the external margin from top. 



Antennules (fig. 17a) chirocerate, very short, composed of 6-seg- 

 ments. Segment 1 fairly long, asetose. Segments 2 to 4 short and 

 particularly setose, as can be seen by reference to figure 17a. Some of 

 these setae are strongly haired. Segments 3 and 4 each with aesthe- 

 tasc, each flanked by 2 setae. Segments 5 and 6 strongly developed, 

 especially segment 5, to form powerful chela. Segment 6 is a flat- 

 tened structure, resulting apparently from the fusion of several smaller 

 segments, beariug 5 short setae. Segment 5 asetose, with a blunt 

 tooth at the base. 



Antenna with slender, 6-segmented exopodite. Segments 1 to 5 

 each with fine seta, segment 6 with 3 setae. Endopodite 3-segmented, 

 number of setae 1, 4, and 6, respectively (fig. 176). 



Mandibular praecoxa well developed, with 5 teeth along cutting 

 edge and a basal seta. Palp well developed, basipodite composed of 

 fused coxa and basis, carrying 2 setae. Endopodite 2-segmented, 1st 

 with 2, 2nd with 6 setae. Exopodite 1-segmented, ovate, with 6 

 setae (fig. 17c). 



Arthrite of maxillule small, with 7 spiniform setae and fine, apical 

 seta. There is one (coxal) endite with 2 setae; epipodite reduced, 

 asetose. Basipodite undivided, with 4 setae. Exopodite distinct, 

 with 7 long setae. Endopodite 2-segmented, with 4 and 5 setae 

 respectively (fig. 17 d). 



Maxilla (fig. 17g) with 1 praecoxal, 2 coxal, and 1 basal endite. 

 Praecoxal endite with 3 setae, coxal endites with 3 and 2 setae re- 

 spectively; basal endite with a strong spine, coalescent with the en- 

 dite, and 3 setae. Endopodite well developed, though undivided, 

 with 7 setae in all. 



Maxillipede (fig. 17/) composed of coxa, basis, and 3 segments. 

 There are 2 setae on a slightly elevated part of the coxa and 6 on the 



