294 U.S. NATIONAL JMUSEUM BULLETIN 236 



plate) of reduced size, represented by small lobe, carrying single 

 seta (fig. 1140- Setal formula: 



endopodite exopodite 



leg 1 0.2 0.0.4 



leg 2 0.3 0.0.013 



leg 3 (modified) 0.0.013 



leg 4 0.3 0.0.013 



Color faded, greenish yellow, without eye or pigmented spot being 

 visible. 



Remarks. — This new species is very near to Orthopsyllus linearis, 

 from which it differs principally by the strongly developed rostrum 

 and the presence of a spine on the 2nd antennular segment. I am 

 inclined to attach little importance to the larger rostrum in the present 

 species: it may be as big as what occurs in 0. linearis; its size in the 

 drawings of that well-distributed species may depend largely upon 

 curvature of the body or the rostrum. Though in the female of 

 0. linearis a spine does occur on the 2nd antennular segment, the 

 male of 0. linearis has been described distinctly as lacking that 

 spine. There are also slight differences in the setal formulae between 

 the female of 0. linearis and the present new species, but these may be 

 due to sexual dimorphism, since, in this genus, female and male of a 

 certain species may have slightly different setal formulae. I have 

 been unable to lift the setal formula of the male 0. linearis from the 

 literature. The presence of the antennular spine particularly induced 

 me to describe the present male as a new species though I have done 

 so with considerable trepidation. 



A single specimen of this new species was washed from sponges on 

 coral rocks in the Ifaluk lagoon. 



Orthopsyllus pectinicauda, new species 



Figures 115c-e, 116a,6, 117, 118, 121a 



Material. — Loc. 431, 2 ad. 99, 0.65 and 0.75 mm.; 1 ad. cf , 0.73 

 mm. Loc. 590, 1 ad. 9, 0.77 mm. Loc. 592, 1 ad. d^, 0.66 mm. 



Description. — The following is based on the female specimen 

 from locality 590 (holotype) and on a male allotype from locality 

 592. Both specmiens have been dissected and mounted. All 

 remaining specimens are designated as paratypes. 



Adult female (loc. 590), total length 0.77 mm.; greatest diameter 

 0.15 mm.; length of longest furcal seta 0.12 mm. 



General shape of body elongated and slender, almost cylindrical, 

 with greatest diameter of body at end of cephalic somite and very 

 slightly tapering posteriorly. Division between cephalothorax and 

 abdomen not marked by constriction but by chitinized ridges on 5th 

 thoracic and genital somites (see below). All somites stand out 



