168 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 112 



fleeted light) opaque white with red areas, mainly in the pro-some 

 around or coloring the oviducts, which tend to give a general reddish 

 appearance on the whole body when viewed with the naked eye; fifth 

 legs and caudal rami occasionally brown; eye and ovisacs bright red. 



Prosomo comprising a ccphalothorax, with no trace of division 

 between cephalosome and first pedigcrous somite, and 3 metasomal 

 segments whose terga are usually imbricate, with square or rounded 

 corners. Prosome ovate but posteriorly truncate in dorsal outline, 

 flattened in side view. Eye of the usual naupliar type. Rostrum 

 (fig. 2b) a small fold, apparently in tcrgum of ccphalothorax, produc- 

 ing this ventrally between bases of antennules. Postoral protuberance 

 inconspicuous. 



Urosome 5-segmented. Largest the genital segment, which almost 

 certainly represents a complex of 2 somites, the boundary between 

 them represented ventrally and occasionally in dorsal view by a 

 thickened ridge. (Light and Hartman, 1937, give a very good picture 

 of this segment in their figure 12. This figure shows the structure of 

 the anterior part of the segment- — i.e., genital somite proper- — with 

 its 2 pairs of small lateral expansions. The dorsal anterior pair of 

 expansions are often joined along the dorsal surface by a thickened 

 strip and make the anterior part of the segment wider than the 

 posterior region — i.e., first abdominal somite.) Paired oviducal open- 

 ings ventrolateral on anterior corners of genital segment. Ovisacs 

 with numerous eggs, usually reaching ends of caudal rami, narrowly 

 cylindrical. Three free abdominal segments, the last here termed 

 the anal segment and carrying a row of fine spinules ventrally along 

 each side of distal border near midline. Anus dorsal, without dis- 

 tinct anal operculum; oval-shaped area in figure 21 having a very 

 thin integument. 



Caudal rami more than 3% times as long as wide; bearing 4 termi- 

 nal setae and an outer lateral and an inner dorsolateral seta, all distally 

 placed. Outermost terminal and usually outer lateral seta comprised 

 of a basal shaft, ending in a small spiniform projection on one or both 

 sides, and a terminal "flagcllum" whose thickening is broken up into 

 transverse rings. Two longest setae with usual "jointed" attachment 

 at base. 



Antennulc 7-segmented. Attachment of basal segment to ventral 

 exoskeleton of head region at right angles to plane of projection of 

 remainder of appendage. Appendage in life carried perpendicular 

 to sagittal plane of body. Last 3 segments slightly narrower than 

 and their axis at an angle to preceding 4. Setation: 4 on first, 15 

 on second, G on third, 3 on fourth, 4 on fifth, 2 and an aesthete on 

 sixth, 7 and an aesthete on seventh. Long setae on fourth and ter- 

 minal segments very obvious. One seta on second and one on fifth 



