COPEPOD GENUS KIDGEWAYIA — ^WILSON 139 



(1911) Bermuda species marki. Among calanoids, the modification 

 of the female fifth leg is distinctive for these species. That of R. 

 typica differs from that of the three American species only in having a 

 shorter inner apical spine on the third exopod segment. This and 

 other differentiating characters are either interpretable as specific, 

 or concern structm-al featm-es that have been sketchily presented, or 

 could have been overlooked. These characters and features are 

 pointed out in the specific diagnoses and discussion. 



When the similarity of the basic characters is considered, it does 

 not seem possible to me that there is any choice other than to refer the 

 Tortugas material to Ridgewayia. It seems inconceivable that 

 Esterly would have erected a new genus for his Bermuda speci- 

 mens had he been aware of and considered the description of R. 

 typica. Since the male of typica is still unknown, there exists no 

 more justification for the genus Lampoidopus today than there did in 

 1911. Gurney (1927) appears to have been unaware of Esterly's 

 paper, since he failed to point out not only the similarity of his Suez 

 Canal specimens with the males described by Esterly, but in the 

 same paper he named a new species of Pseudocyclops without noting 

 its striking similarity to P. magnus described in Esterly's Bermuda 

 paper. It also seems inconceivable that if Gurney had referred in his 

 study to both Esterly's and Thompson and Scott's papers that he 

 would have failed to note the relationship of his specimens to Ridge- 

 wayia, as shown through Esterly's description of both sexes. Krish- 

 naswamy also makes no mention of Ridgewayia or of Lampoidopus. 

 Thus, all the authors who have reported species of this group since the 

 original description of Ridgewayia typica have failed to relate their 

 material to it. Sewell (1929, 1932, 1948), in summaries of copepods 

 of Indian waters, has not included R. typica, although Suezia is men- 

 tioned. The genus Ridgewayia has therefore in effect become buried 

 in the literature. 



The generic diagnosis given herein for Ridgewayia is a composite 

 of the characters of both sexes of all the known species. It is detailed, 

 contains exceptions and alternatives, and points out- wherein knowl- 

 edge is not complete for some species. Such a diagnosis is intended to 

 form a working basis for the present report and also to be useful in 

 future studies. In searching for the characters that indicate rela- 

 tionship of a group of calanoid species to one another, either on the 

 generic or familial level, it is necessary to consider every appendage. 

 In the species dealt with here, the evidence for their very close rela- 

 tionship is found in all appendages. Particularly noteworthy is the 

 correlation of all oral appendages, the maxilliped and the first and 

 fifth legs. The characteristics of these appendages in large groups may 

 define a family, but they are also highly pertinent at the generic level 



