74 U.S. NATIONAL MUSEUM BULLETIN 236 



Turkey (9 480ju). In the Ifaluk collection it occurred once in a 

 washing of the alga Caulerpa and in abundance in sand samples taken 

 at various distances from the reef edge. It might be considered 

 tentatively as a characteristic element of the Ifaluk interstitial sand 

 fauna. 



Genus Halophytophilus Brian, 1918 



This genus now comprises the following four species : H. fusiformis 

 Brian, 1918 (type species), H. spinicornis G. O. Sars, 1920, H. similis 

 Lang, 1948, and H. triarticulatus Klie, 1949. All specimens in the 

 Ifaluk collection plainly represent H. jusiformis and are all females. 



Halophytophilus fusiformis (Brian, 1918) 



Figures 19c-e, 23 



Alophytophilus fusiformis Brian, 1917, p. 177 (nomen nudum); 1918, p. 74, figs. 

 1-10. 



Halophytophilus fusiformis. — Sars, 1920, p. 48. — Brian, 1921, p. 56, pi. 11 (figs. 

 12-17) ; 1923, p. 129; 1923a, p. 176; 1928, p. 36; 1928a, p. 298, 305.— Monard, 

 1928, p. 296, fig. 4 (no. 1), fig. 6 (no. 2).— Vatova, 1928, p. ISO.— Monard, 

 1935, p. 23; 1935a, p. 11; 1936, p. 50; 1937, p. 35.— Lang, 1948, p. 249, fig. 

 130 (no. 1).— Klie, 1949, p. 106. 



Material. — Loc. 431, 1 ov. 9, 0.26 mm. Loc. 638, 1 ad. 9, 0.38 

 mm. Harry Sta. 41, 1 ad. 9, 0.28 mm. 



Description. — The three female specimens present show a con- 

 siderable discrepancy in length (0.26-0.38 mm.). The following is 

 based on the smallest specimen from locality 431, which was found first. 



Adult female, total length 0.26 mm.; greatest diameter 0.05 mm,; 

 length of longest f ureal seta 0.10 mm. 



Small, compactly built species with short, spindle-shaped body. 

 Greatest diameter at end of cephalic somite, very gradually narrowing 

 posteriorly, frontal part ovoid, obtuse at rostral base (fig. 19c). Abdo- 

 men and cephalothorax not distinctly separated. Head and 1st 

 thoracic somite completely fused to form cephalic somite, which is as 

 long as combined lengths of thoracic somites 2 to 5. In lateral aspect 

 (fig. 19(/), line of back smoothly curving into rostrum. Latter a down- 

 wardly directed, triangular plate with rather broad base and pointed 

 at apex, only the base visible from above. Thoracic somites 2 to 4 of 

 about same length, short. 5th thoracic somite slightly shorter than 

 preceding somite, remarkable by its distal dorsal border, which shows 

 small notch on each side. 



Abdomen Yz length of cephalothorax. Genital somite resulting from 

 fusion of abdominal somites 1 and 2, no line of fusion being visible. 

 It is only slightly longer than abdominal somites 3 or 4, which have 

 the same length. Fine row of hairs along ventral distal border of 4th 

 abdominal somite (fig. 19e). Anal somite about half length of 4th, 

 deeply cleft; anal flap small, placed proximally, Kami of furca diverg- 



