142 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



mation on setae of basipods otherwise incomplete in literature; the 

 new species and marki have inner setae on both basipod segments of 

 leg 1, and on basipod 1 of legs 2-4; legs 3 and 4 entirely unknown for 

 canalis; leg 3 unknown for typica.) Exopod segments 1 and 2 with 

 one outer spine and inner seta. Exopod segment 3, total number of 

 outer and terminal spines (so far as known): three on legs 1 and 2, 

 four on legs 3 and 4; these spines mostly without serrations or mem- 

 branes; total number of inner setae: four on leg 1; five on legs 2-4. 

 Endopod segment 1 with one inner seta on all legs ; endopod segment 2 

 with two setae on legs 1 and 2, and on leg 3 where Imown; one or two 

 setae on leg 4. Endopod segment 3, total of six setae on leg 1 ; eight 

 on leg 2; five to eight on leg 3; six or seven on leg 4. Most of the 

 setae divided into two joints, consisting of a stiff basal cylinder and a 

 longer, flexible distal part, densely plumose. 



Leg 5 of female showing only slight specific differences, slender, 

 symmetrical, with well-developed 3-segmented exopod and reduced 

 2-segmented endopod. Exopod modified; segment 3 constricted 

 basally and set into narrowed, well-defined socket of segment 2; the 

 outer, distal spine-bearing portion of segment 2 enlarged and consid- 

 erably produced beyond this insertion. Exopod segment 3 with four 

 spines and four inner marginal setae. Endopod segment 1 reduced, 

 without inner seta. Endopod segment 2 at least twice the length of 

 first segment and usually longer; with seven setae (two outer, two 

 apical, three inner). All setae with jointed bases. 



Leg 5 of male: Right and left basipod segment 1 fused or with 

 definable connecting plate. Both rami modified and strongly asym- 

 metrical. Right exopod 2-segmented, sometimes with imperfectly 

 separated apex; second segment tendmg to elongation, with two outer 

 marginal spines, or with one proximal spine and more distally placed 

 spinous points; the segmental portion beyond proximal spine nar- 

 rowed and more or less incurved. Left exopod 3-segmented, or third 

 segment not entirely separated from second (as in Gurney's figure for 

 canalis) ; the whole third segment or apical portion considerably modi- 

 fied, with a short but stout basal portion from which may extend 

 spines, complex ornamented processes and fragmented membranes of 

 irregular length. Endopods unsegmented; the right elongate, nearly 

 as long as or longer than exopod ; the left much shorter than the right 

 (tending to bo about half as long or less); either endopod entu-ely 

 unarmed, or with setae, spines or processes. 



Type species: Ridgeicayia tyjnca. 



Ridgewayia typica Thompson and A. Scott 



Ridgewayia typica Thompson and A. Scott, 1903, p. 245, pi. 1, figs. 1-13. 



Diagnosis (after Thompson and Scott): Female: Length about 

 0.85 mm. Metasome of six well-defined segments, the somite of leg 1 



