200 SPOLIA ZEYLAJSflCA. 



As a result of a careful study, it appears that the sole 

 appreciable difference between these forms lies in the structure 

 of the fifth pair of legs. The question then arises, Are we 

 justified in considering these forms to be distinct " species " ? 



Examples of variation in the structure of the sexual appen- 

 dages have been described in other species, e.g., Labidocera 

 hroyeri (Brady) ; and the similarity of the two forms is so 

 close, even to the lengths of the antennal segments and the 

 proportions of the swimming feet, that I submit we could only 

 get such a close resemblance in individuals of the same species, 

 and I believe that the form described by Giesbrecht under the 

 name Calanus caroli is merely a variation of the male of 

 Undinula darwini. 



Genus Eucalanus, Dana. 



EucALANUS ATTENUATUS (Dana). 



Eucalanus attenuatus, Thompson, 1899, p. 276. 



. Cleve, 1901, p. 6. 



— Cleve, 1903, p. 362. 



_ — Thompson & Scott, 1903, p. 242. 



Wolfenden, 1903-06, p. 996. 



Cleve, 1904, p. 189. • 



— Sewell, 1912, p. 357. 



A few examples occurred in the collection from the pearl 

 banks. 



Eucalanus subtenuis, Giesbrecht. 



Eucalanus subtenuis, Cleve, 1901, p. 7. 



Scott, 1902, p. 401. 



Cleve, 1903, p. 363. 



Thompson & Scott, 1903, p. 242. 



Wolfenden, 1903-06, p. 996. 



Cleve, 1904, p. 190. 



Scott, 1909, p. 21. 



, Sewell, 1912, p. 358. 



This species was on the whole well represented in the collec- 

 tions. 



