364 U.S. NATIONAL MUSEUM BULLETIN 236 



p. 554, fig. 159a) and the present specimen. The lateral cephalic 

 expansions in Gurney's specimen appear to have been obtusely 

 pointed; they are rounded in the Ifaluk specimen. A median cephalic 

 carina appears to have been present in Gurney's specimen; in the 

 Ifaluk specimen indications of a carina occur behind the rostrum, 

 followed by a deep depression extending as far as the cephalic spine; 

 this condition does not appear from Gurney's description, nor from 

 his figure. Two cephalic depressions are mentioned in Willey's 

 description (Willej^, 1930, p. 107, fig. 65), but in his observations of 

 the lateral aspect of the animal the exact size of the depressions may 

 have been obscured by the lateral swellings. Willey's observation, 

 therefore, may have been incorrect. The Ifaluk female, in body 

 shape, is identical with L. steueri van Douwe, 1929 (pp. 286, 291, 

 figs. 16-21), a species considered identical with L. armiger. Since 

 there are no differences in the structure of any of the appendages, it 

 seems likely that in the shape of the body there is, in this species, a 

 considerable degree of variability. 



The geographical distribution of this species has been discussed by 

 Lang (1948, p. 1424). It has been recorded from the Atlantic coast 

 of Brazil (Carvalho, 1952), from the Bermuda Islands (WiUey, 1930), 

 from various localities distributed over the whole Mediterranean (see 

 Lang, 1948), and from the Suez Canal zone (Gurney, 1927). Two 

 specimens were found in sand samples taken 60-80 feet from the reef 

 margin on Falarik in the Ifaluk Atoll; they apparently represent 

 the first Pacific specimens. The length of the Atlantic and Mediter- 

 ranean specimens, according to Lang, is 9 0.48-0.65 mm., cf 0.49-0.54 

 mm. 



Onychocamptus gladiator, new species 



Figures 1446,c, 145, 146a,6 



Material. — Loc. 638, 1 ad. 9, 0.42 mm. 



Description. — The following is based on the above-mentioned 

 specimen (holotype), which has been dissected and mounted. 



Adult female, total length 0.42 mm.; greatest diameter, measured 

 between spines of cephalic somite, 0.12 mm.; length of longest f ureal 

 seta 0.30 mm. 



General shape of body resembling that of Onychocamptus brevispi- 

 nosus G. O. Sars; body is slender, slightly depressed dorsoventrally, 

 without distinct separation between cephalothorax and abdomen. 

 Greatest diameter of body between cephalic lateral spines; body 

 narrows very gradually posteriorly and is slightly dilated in genital 

 region (fig. 1446). Head and 1st thoracic somite completely fused, 

 cephalic somite as long as combined lengths of thoracic somites 2 to 

 5. Shape of cephalic somite very characteristic; can best be appre- 



