COPEPOD GENUS RIDGEWAYIA — WILSON 157 



distal process short; the basal process nearly as long as the endopod 

 (in dissections, this process found expanded as shown in fig. 27, or 

 entirely "pulled in" and lying along the margin of the endopod). 



Ridgewayia shoemakeri, new species 



Figures 28-35 



Specimens examined: 2 females, 13 males. Occurring with R. 

 gracilis in the vicinity of Loggerhead and Bush Keys, Dry Tortugas, 

 Fla., July 23-Aug. 12, 1926, Clarence R. Shoemaker. 



Types: Holotj^pe female (slides) USNM 99517; allotype male 

 (slides) USNM 99518. Paratype specunens (slides and alcoholic) 

 in U. S. National Museum collections. 



Diagnostic characters: Urosome female 4-segmented, segments 

 with distal serrate fringe; male 5-scgmented; the two middle caudal 

 setae not jointed basally in either sex. Antennules, female and left 

 male, 26-segmented; segments 13-22 with row of spinules extending 

 across distal edge of segment. Right antennule male 24-segmented, 

 with four segments beyond geniculation ; segment preceding genicula- 

 tion without lateral comblike row of spinules. Maxilla with six 

 inner lobes, of which two belong to basal division. Total number 

 setae, endopod 3, legs 1-4: 6, 8, 8, 7. Leg 5 female, inner apical 

 spine exopod 3 longer than outer spines, about as long as segment. 

 Leg 5 male, right exopod 2, first outer spine only little longer than 

 second spine; left exopod 3-segmented, outer spine of segment 2 

 reaching to end of modified processes of segment 3; right endopod 

 with slender outer seta; left endopod unarmed. 



Female 



Length, dorsal midline, 0.67-0.68 mm. Body slender, but lacking 

 the erect appearance of gracilis, due to the strong cm*vature of the 

 forepart of the cephalic segment (as sho^vn for male, fig. 32). Pro- 

 portions and segmentation of metasome very similar to those of 

 gracilis. Cephalic segment longer than rest of metasome (about 

 80:71). Segments 5 and 6 both reduced in midline; wings of last 

 segment like those of gracilis, except that the outer notch of the 

 posterior edge is not enlarged. 



Urosome segmented as in gracilis, the fourth being likewise reduced 

 to the width of the caudal rami. Relative lengths of the segments 

 and rami: 



1 2 3 4 CR 



20 8 6 2 13 



