COPEPOD GENUS EIDGEWAYIA — WILSON 177 



term Calanoida, which, though equivalent to Giesbrecht's term Gjmi- 

 noplea, has long been preferred and extensively used. Lang's com- 

 ments on the systematics of the Copepoda are brief and in part in- 

 conclusive, but the concepts presented are worthy of consideration 

 by systematists. Attention is drawn here to Lang's paper because 

 it is one that may easily be overlooked by specialists in the Calanoida. 



Habitat and distribution 



The existing records of Ridgewayia are all from tropical or subtrop- 

 ical coastal areas. Although they suggest that the species may be 

 somewhat localized, they are too few to verify such a suggestion. 

 They more strongly support the indication that the genus is not a 

 pelagic form. This indication is not refuted by the instances in which 

 it occurred in plankton hauls because the records of occurrence are 

 so few and only one or two specimens were captured. Hauls reported 

 by Gurney and Pinney were made at night when bottom copepods 

 may ascend to higher water levels. Gurney interpreted Suezia canalis 

 as "a species living on the bottom during the day" and included the 

 record in the report on the littoral rather than the pelagic Copepoda 

 of the Suez Canal. 



The four species represented in collections by several specimens 

 were all found in comparable situations. Specimens of R. typica were 

 found in sediment from oyster shells taken on a reef; marki occurred 

 in an island cave dominated by the coral Agaricia gracilis; and the 

 two new species from the Dry Tortugas were associated with corraline 

 algae. The warm, shallow waters of tropical and subtropical reefs 

 and rocky shores, particularly among islands, is therefore suggested 

 as a common habitat of the genus. This is unusual for Calanoida, 

 but it is such a little-investigated habitat of Copepoda that our in- 

 formation concerning the calanoids that may occur in such situations 

 is very meager. 



That the genus may also be a bottom-living form of deeper coastal 

 waters is suggested by the records in which the species occurred in 

 plankton hauls. Aside from the investigations made by Thomas Scott 

 and G. O. Sars on the north European coast, the bottom-living 

 calanoids are practically unknown. Since Scott and Sars found 

 several genera and species not closely related to one another or to 

 known pelagic genera and families, it would appear safe to hazard the 

 guess that there may exist other species, genera, or even families of 

 Calanoida that are as yet undiscovered. There are published records 

 of only five genera of this habitat gi-oup from American waters. 

 Psevdocyclops has been recorded from northern Canadian waters by 

 C. B. Wilson (1936) and from Bermuda by Esterly (1911). A new 



