COPEPODA FROM IFALUK ATOLL 373 



3rd exopodal segment of legs 2 to 4 short, external marginal spines 

 slender, all appendages inserting close together. 2nd endopodal seg- 

 ment of legs 2 and 3 with apically inserting setae. Leg 5 with long 

 and slender baso-endopodite, bearing 4 setae. Exopodite elongated 

 triangular, with 5 short, marginal setae. 



Males unknown. 



Type and sole species: Microlaophonte spongicola, new species. 



Microlaophonte spongicola, new species 



Figures 141o,6, 146/-A, 147 



Material.— Loc. 594, 4 ad. 99, 0.38-0.48 mm. (0.43 mm.). 



Description. — An adult female of 0.46 mm. has been selected as 

 the holotype; the following is based largely upon this specimen. 

 Some information also has been gained from the remaining (paratype) 

 specimens, all of which have been dissected. 



Adult female, total length 0.46 mm.; greatest diameter 0.11 mm.; 

 length of longest f ureal seta 0.18 mm. 



Body very slender, greatest diameter at end of cephalic somite, 

 anteriorly rounded, posteriorly very gradually narrowing, mthout 

 any trace of division in cephalo thorax and abdomen. Body, more- 

 over, cylindrical, not depressed (figs. 141a,6). Cephalic somite formed 

 by complete fusion of head and 1st thoracic somite, short, as long 

 as combined lengths of thoracic somites 2 to 4. Sides of cephalic 

 somite produced to cover the oral appendages. Back, in lateral 

 view, slightly curved, running imperceptibly into short rostrum (fig. 

 1416). Rostrum in dorsal aspect short, compact plate with broad 

 base, free margin sinuous, with two hairs of frontal organ. Thoracic 

 somites 2 to 5 of equal length; epimeral plates moderately produced, 

 rounded. Some knobs occur along dorsal part of distal border of 

 somites 4 and 5. 



Genital somite composed of fused abdominal somites 1 and 2, 

 which have equal length; line of fusion distinct on dorsal surface. 

 3rd abdominal somite longer than preceding; 4th somite short. Ab- 

 dominal somites 2 to 4 distally with fine spinules or knobs along 

 dorsal and laterodorsal margin. Anal somite as long as wide; anal 

 plate broadly rounded, spinulose; somite deeply cleft between insertion 

 of caudal rami. 



Caudal rami cylindrical, 3K times as long as wide, internal margin 

 very slightly concave. 5 marginal setae and 1 appendicular seta, 

 inserting very closely together at caudal end of each ramus. All are 

 short with exception of seta 2, which, on each side, is greatly 

 lengthened and thickened. 



Ventral aspect of genital area represented in figure 147i, from which 

 it appears that epimeral plates of abdominal somites 1 to 3 are 

 slightly lateroventrally produced and pointed. 



