COPEPOD GENUS RIDGEWAYIA — ^WILSON 155 



of small spinules. Exopod segments 1 and 2 with stout outer spines 

 armed marginally with serrate flanges; segment 2 with an inner, 

 jointed seta, the stiff basal portion of which reaches more than halfway 

 to the base of the first seta of segment 3. Exopod segment 3 with 

 a group of three outer, serrate spines, all shorter than the segment; 

 the two proxunal spines placed margmally, the distal apically; the 

 fourth spine (inner apical) with outer hyaline flange, about as long 

 as the segment and nearly twice the length of the distal outer spine 

 (about 60:35). The basal portions of the jointed setae of the mner 

 margin of exopod 3 all reach beyond the base of the succeeding seta. 

 Segment 1 of the endopod without seta; its outer distal margin pro- 

 duced to point. Segment 2 with seven jointed setae, the basal portion 

 of each of the three inner setae reach beyond the base of the succeeding 

 seta. The first outer seta placed just below the middle of the segment 

 (at a point representuig about 60 percent of the length of the inner 

 margin of the segment); the first inner seta placed above the middle 

 of the segment (at about 36 percent). Apical outer spinous process 

 and basal portion of apical setae long, the process 20 percent, the 

 setal bases 54 percent of the length of the inner margin of the segment. 

 (See also p. 170.) 



Male 



Length, 0.8 mm. Habitus as in female. Urosome 5-segmented, the 

 first four segments subequal to one another in length, the fifth reduced 

 as in the female. Caudal rami and setae exactly like those of female. 



Rostrum enlarged as in female, with broader tip and separated 

 from forehead by a distinct surface demarcation across its entire base. 

 All appendages except right antennule a,nd fifth leg like those of female. 



Left antennule 26-segmented and with setation as in female. 

 Right antennule with proximal segments as in female; midportion 

 modified in that segments 13 and 14 are fused outwardly and im- 

 perfectl}^ divided from one another by a deep cleft beginning at the 

 inner margin and extending irregularly into the middle of the segment 

 (fig. 23). The antennule with 23 apparent free segments (counting 

 13 and 14 as two segments). The four apical segments elongated 

 and of similar length (fig. 22); the point of geniculation between the 

 proximal two of these segments (segments 20 and 21) so that there are 

 three segments bej'ond the geniculation. Segment 20 with a longi- 

 tudinal row of spinules arranged as a comb along the distal inner 

 half. (See p. 163 for interpretation of segmentation.) 



Ijeg 5 (figs. 24-27): Fh-st basal segments fused, forming a narrow 

 crosswise bar to which the enlarged second basal segments are at- 

 tached. Right basipod 2 longer than left, each with outer distally 

 placed spinous process and submarginal seta. Right exopod: Seg- 



