of the Fishery Board for Scotland. 237 



CRUSTACEA. 



SUB-CLASS ENTOMOSTRACA. 



Order I. COPEPODA. 



Calanid^e. 



Eucalanus elongatus (Dana); and Eucalanus crassus, Giesbreclit. 



T have at different times during the past few years recorded these two 

 species of Eucalanus from the north-east and north of Scotland, and this 

 year I have again to note their occurrence in Scottish waters, but from a 

 locality different from those previously mentioned — viz., at about fifty 

 miles south-east of the Fair Island, between Orkney and Shetland. They 

 were obtained in at least two tow-net gatherings collected on October 

 19th, 1900, by the steam trawler "St. Andrew." A number of specimens of 

 both species were observed in this gathering. 



Rhincalanus (?) gigas, Brady. (PI. XVII., figs. 1-4.) 



Rhincalanus gigas, Brady, Challenger Reports, vol. viii., Copepoda, 

 p. 42, PI. VIII., figs 1-11. 



Several specimens of a Rhincalanus, apparently belonging to R. gigas, 

 Brady, were obtained in one of the tow-net gatherings collected to the 

 eastward of the Fair Island, in which the two species of Eucalanus 

 mentioned above were observed. Most of the specimens were females, 

 and were apparently adult ; about half a dozen males were also observed,, 

 but they were considerably smaller than the females, and appeared to be 

 scarcely mature. 



The only apparent difference between these female specimens and 

 R. gigas, Brady, is in their size. The specimens of Rhincalanus gigas 

 described by Dr. Brady measured from 8*5 to 10 millimeters, while those 

 collected to the eastward of the Fair Island were 5 mm. in length. In 

 these specimens the fifth pair of feet in the female are identical in form 

 and armature with those of R. gigas. Figures 10 and 11 of Plate VIII. 

 in Dr. Brady's " Challenger" Report probably represent the fifth feet and 

 abdomen of a male specimen ; they resemble closely figures 2 and 4 on 

 Plate XVII. of this paper, which represent similar parts of one of the 

 immature males in the collections from the Fair Island. Figure 3 (Plate 

 XVII.) represents the last thoracic segment and abdomen of one of the 

 female specimens. I am inclined to ascribe the Fair Island specimens to R. 

 gigas, though they are somewhat smaller than those recorded by Dr. 

 Brady, rather than to R. nasutus, Giesbrecht. It may also be noted in 

 passing that R. nasutus is in some respects, and especially in the form 

 of the female fifth feet, not very unlike R. gigas, Brady. 



Stephus gyrans (Giesbrecht). 



1892. Mobianus gyrans, Giesbrecht, Pelagischen Copep. d. Golfes 



v. Neapel, p. 205, PI. 5, 9, 35. 

 1897. Stephus gyrans, T Scott, Fifteenth Ann. Rept., Part III., 



p. 146, PI. II., fig. 9; PI. Ill, figs. 17, 18. 



This distinct species was recorded for Loch Fyne in 1897, and up till 

 last year this was the only Scottish locality where Stephus gyrans had 

 been observed ; now, however, I am enabled to record it from a second 



