40 U.S. NATIONAL MUSEUM BULLETIN 236 



5. Antennules 18-segmented E. sewelli, new species 



Antennules 21-segmented 6 



6. Median apical spine 3rd endopodal segment of leg 4, 1% times as long as 



3rd endopodal segment. Cephalic somite short; antennules just reach end 



of cephalic somite E. brevicauda Sewell 



Median apical spine of 3rd endopodal segment of leg 4, % the length of the 

 3rd segment. Cephalic somite large, antennules scarcely reach beyond 

 the middle of that somite E. pseudorobusta, new species 



Euryte pseudorobusta, new species 



Figures 8-10 



Material. — Loc. 589, 1 ad. 9, 0.53 mm.; 1 ad. cf , 0.53 mm.; 2 juv., 

 0.37 and 0.47 mm. (developmental stage unknown). Loc. 590, 2 

 ad. 99, 0.53 and 0.60 mm.; 1 ad. d", 0.46 mm.; 2 99 cop. stage V, 0.48 

 and 0.51 mm. Loc. 591, 3 ad. 99, 0.56, 0.60, and 0.65 mm.; 1 ad. cf , 

 0.47 mm. 



Description. — The following is based on the female of 0.65 mm. 

 length from locality 591 (holotype) and on the male (allotype) from 

 that locality. All remaining specimens are paratypes. The speci- 

 mens described have been dissected and their appendages mounted. 



Adult female, total length 0.65 mm. (0.53-0.65 mm.). Propor- 

 tional length of cephalothorax and abdomen is 11:9. Greatest 

 diameter 0.23 mm.; length of longest furcal seta 0.20 mm. 



Gracefully built species, with slender, elongated, ovate cephalo- 

 thorax and distinctly set off, slender abdomen (figs. 8a, 6). Cephalo- 

 thorax distinctly compressed dorso ventrally ; head and 1st thoracic 

 somite completely fused to form cephalic somite, which takes con- 

 siderable part of cephalothorax. Cephalic somite dorsally with broadly 

 rounded anterior portion, slightly narrowed between insertion of 

 antennules, base of rostrum again broadly rounded. In lateral aspect 

 back almost straight, anteriorly broadly rounded and curving almost 

 imperceptibly into rostral plate. Rostrum attached with broad base, 

 invisible from above, pointing downward and slightly backward, 

 triangular, apex rounded. 2nd and 3rd thoracic somites of about 

 same length; 4th thoracic somite notably small, in dorsal view cut 

 off almost squarely, in lateral view rounded. The various parts of 

 the cephalothorax have the following proportional lengths : 



somite head+1 2 3 4 



70 11 l3 6=100. 



5th thoracic somite small, laterally produced into pointed, wing- 

 shaped expansions; points directed laterally and slightly backward. 

 Genital somite composed of fused abdominal somites 1 and 2, line of 

 fusion visible on back and partly on sides. In dorsal view genital 

 somite appears to be produced into number of tubercles (fig. 8a) . Distal 



