COPEPODA. 
O 
o 
RHINCALANUS (Dana). 
(Plate II ., fig. 6.) 
Rhine, grandis, Giesbrecht, ‘Belgica’ Rep., p. 18. 
? Rh. gigas, Brady, ‘ Challenger ’ Rep. XIX., p. 42. 
„ Scott, 19th Rep. Scotch Fishery Board (1901), p. 237. 
„ Giesbrecht, Fauna u. FI. Xeap. XIX. (1892), p. 153. 
Rh. gigas was described by Brady as distributed over a very wide area between 
long. 53° 32' W.—130° 52' E. and lat. 36° 44' S —65° 42' S. Much doubt has been 
expressed by Giesbrecht as to the validity of this species, and the figures given by 
Brady of abdomen and of the whole animal are those, in Giesbrecht’s opinion, of 
immature animals, and this author thinks that Brady’s figure of the first feet is really 
of one of the other pairs of feet. 
Scott’s specimens (Fair Isle and Firth of Forth) are regarded by Giesbrecht as 
Rh. nasutus ( Th. 3 and 4 with dorsal or with a lateral spine, as in nasutus, and a pair of 
small dorsal points on the genital segment). Mobius’s specimen from the north of 
Scotland is also identical with nasutus. Rh. nasutus is very common in the Faroe 
Channel and seas off the north of Scotland, and occurs abundantly in my collections 
made in these regions and along the Atlantic trough, west of Ireland, and also 
appears in the ‘ Gauss ’ collections as far south as lat. 20° N., while in the same 
collections Rh. grandis (Giesbrecht) appeared. From the remarks of Sars in 
“Crustacea of Norway,” Vol. IV., p. 15, it might be inferred that Rh. nasutus is of 
rare occurrence in the Northern Ocean (“ two specimens were taken east of Iceland, 
one specimen by Hjort between Scotland and Norway, and it has not yet been found 
in the immediate vicinity of the Norwegian coast.”) However I have taken it in 
abundance on many occasions throughout the Faroe Channel. It is rather important 
to establish the identity of Brady’s Rh. gigas, and of two preserved specimens at the 
British Museum, which I have examined, one measured 5'8 mm. and another 6'0 mm. 
Both were immature females with four-jointed abdomen, lateral spines on Th. 3 
(small), and on Th. 4 (large), with none on the fifth segment, resembling Rh. grandis, 
one dorsal spine on the first abdominal segment (no dorsal spines on the thoracic 
segments), and so far as could be seen without dissection, the first feet had an 
exopodite of two segments only, and the fifth pair consisted each of only one ramus 
of three segments. These two animals were, of course, very much smaller than 
described by Brady (8‘5-10 mm.) and were undoubtedly immature, and the species 
may well be identical with young Rh. grandis (Giesbrecht). 
