2 PROCEEDINGS OF THE NATIONAL MUSEUM vol. m 



of typical caligoid form. Abdomen 1 -segmented. Caudal rami conspi- 

 uous. Egg strings uniseriate. 



Diagnosis applies to both sexes except where noted. 



Type-species. — Caritus serratus, new species. 



Etymology. — From Latin, masc, "lacking, devoid of," alluding 

 to lack of postantennal process and sternal furca. 



Caritus serratus, new species 



Material studied. — 4 females, 1 male from the gills of 2 specimens 

 of Chanos chanos (Forskal) collected at Nosy Be, Malagasy Republic, 

 April 1964. Holotype female, USNM 120352. Allotype male, USNM 

 120353. Three paratype females, USNM 120354. One paratype female 

 dissected for study. 



Female. — Body form as in figure 1. Total length and greatest width 

 (measured at cephalon) of 3 undissected specimens 5.1 x 2.2 mm, 

 5.0 x 2.3 mm, and 4.3 x 1.9 mm. Cephalon comprising nearly one-half 

 of body length, about as wide as long. Genital segment markedly 

 triangular; narrowest anterior, widest posterior, about as long as 

 wide (1.7 x 1.7 mm in 1 specimen). Abdomen 1-segmented (1.2 x .46 

 mm in 1 specimen); widest near middle, tapering only slightly to 

 proximal and distal ends with slight constriction near distal end. 

 Caudal rami (fig. 2) lamellif orm ; about 3 times as long as wide (420^ x 

 147^ in 1 specimen), bearing 6 short, naked setae arranged as in the 

 figure. 



First antenna (fig. 3) 2-segmented; first segment bearing numerous 

 stout plumose setae along anterior margin, 2d segment bearing fewer 

 naked setae near distal tip. Second antenna (fig. 4) 4-segmented; 

 terminal segment in form of a stout claw, armed with 2 small setae 

 as in figure. Mouth tube and mandible of usual caligoid form. Mandible 

 with 12 teeth at tip. First maxilla (fig. 5) consisting of strong post-oral 

 process and basal lobe bearing 3 naked setae. Second maxilla 2- 

 segmented; tip of last segment as in figure 6. Maxilliped (fig. 7) in 

 form of stout claw. 



Legs 1-3 biramose. Leg 1 (fig. 8) with inner and outer short plumose 

 setae on basipod; exopod 2-segmented armed as in figure, endopod 

 1-segmented with very small spine on inner distal corner. Inner 3 

 setae on last exopod segment plumose as in figure 9. Leg 2 (fig. 10) 

 rami 3-segmented. Spines on outer distal corners of first 2 segments 

 of exopod conspicuously toothed on inner margins, large distal spine 

 on terminal segment with broad hyaline border. Leg 3 (fig. 11) coxo- 

 basipod forming a broad lamella, rami small. Exopod 3-segmented 

 without setae; spine on outer distal corner of first segment prominent, 

 others reduced as in figure. Endopod 2-segmented; each segment 



