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70 PROCEEDINGS OF THE NATIONAL MUSEUM vol. us 



like formation of dorsal cuticle. Genital segment (figs. 4/, h) approxi- 

 mately equal to combined lengths of three free thoracic segments, 

 lateral margins flatly concave, dorsal posterior surface flatly concave, 

 ventral posterior surface with V-shaped incision, apex of V at anterior 

 end of abdomen, lateral surfaces of V covering most of ventral ab- 

 dominal surface. Abdomen 1 -segmented, broader anteriorly than 

 posteriorly. Caudal rami slightly longer than m female, without 

 expanded proximal region. 



Antennule (fig. 5c) of female and male 6-segmented, attached 

 to ventral cephalothoracic surface just inside anterolateral corner of 

 hood-shaped cuticular covering of cephalon and just anterior to 

 scoop-shaped ventrolateral projections. First segment approximately 

 one-tliird the total appendage length, sHghtly swollen proximally and dis- 

 tally, with single, setule-like process on distal inner surface. Second 

 segment approximately one-sixth the appendage length, narrow prox- 

 imally, flaring somewhat irregularly distally to broad distal end, with 

 minute, spikelike process on inner medial surface and small setule just 

 distal to it. Third segment approximately one-eighth the appendage 

 length, varying little in width. Fourth segment approximately one- 

 sixth the appendage length, narrow proximally, flared slightly towards 

 slightly swollen distal end. Fifth segment approximately one-eighth 

 the appendage length, slightly wider distally than proximally, with 

 minute spike on distal inner surface. Sixth segment short, length 

 approximately one-twelfth that of appendage, slightly wider distally 

 than proximally distal surface rounded, bearing approximately 6 

 minute, stiff, setule-like projections from inner surface, 4 from medial 

 surface and single, small, spikeline projection from outer surface. 



Female antenna (fig. bd) 4-segmented, not 5 as Shiino (1955c) 

 indicates. Proximal half of appendage capable of being withdrawn 

 into deep socket in ventral surface of cephalothorax just medial and 

 slightly posterior to antennule base (fig. 56) but proximal end of append- 

 age with flexible arthrodial membrane that may appear segment- 

 like (see fig. bd for depiction of musculature) . Fu'st segment approxi- 

 mately one-third the appendage length, relatively narrow although 

 slightly swollen proximally and distally, distal margin irregular. Sec- 

 ond segment slightly more than one-fourth the appendage length, 

 angled proximally and distally, overlapping outer surface of fust and 

 third segments. Exact nature of second segment questionable due to 

 rather indistinct break between adjacent segments although muscu- 

 lature apparently associated with segment and adjacent segments sug- 

 gests the term segment is applicable. Thu-d segment slightly more 

 than one-thu'd the appendage length, larger proximally than distaUy, 

 inner surface with large, roughened, spike-shaped projection medially. 

 Irregular distal margin angled proxmiaUy from outer to inner lateral 



