1898.] PLANKTON OP THE PAEBOE CHANNEL. 541 



and appears to be equally prevalent at all depths. But probably 

 no other known species exhibits this ubiquitous feature to an)'thing 

 like the same extent. A reference to the distribution table will 

 show that several species, such as Heteroelia'ta ahyssalis, were not 

 found at a less depth than 100 fathoms ; while others, such as tbe 

 well-known and beautifully coloured Anomalocera pate^^soni, usually 

 remain about the surface, sometimes congregating in vast numbers. 



The relative sizes of the same species at opposite depths is to a 

 considerable extent seen in Calanns finmarchicus, the deep speci- 

 mens being considerably larger than those found near the surface. 

 Among our British Copepoda the largest known species is 

 Euchceta norvegica, but I am not aware that it has ever been taken 

 in our waters at less than 80 or 100 fathoms, at which depth I have 

 taken it in quantities in Loch Fyne, where it probably forms an 

 important item in the diet of the herring. 



The vertical distribution of Copepoda is doubtless to a consider- 

 able extent subject to climatic influences. During a continuance 

 of stormy weather they often altogether desert the near surface 

 and go very deep ; while in tine warm weather many species 

 love to gambol on the actual surface, presenting much the appear- 

 ance of the " play " of the herring in miniature. 



The size of mesh in the tow-net used is of considerable import- 

 ance, and the apparent scarcity of such minute forms as Oiihona 

 spinifrons and Evf in osotna atlanticum is probably to he explained from 

 the fact of a lai-ge mesh having been generally used ; while the 

 comparatively few tow-nets in which the above species were found 

 were of a fine texture and probably might with advantage have 

 been more generally employed. 



Five out of seven species of Copepoda found by Dr. Brady in 

 material from theEaeroe Channel (Exploration of the Faeroe Channel 

 during the summer of 1880 in H.M.'s hired ship ' Knight Errant ' 

 by Staff-Commander Tizard, E.IN'., and John Murray) occur in this 

 collection, viz. : Eucalanvs attenuatiis, Geniropages typicus, Anomalo- 

 cera patersoni, Acartia longiremis, and Oltliona spinifrons. 



The following species, viz., JEtklius armatus, Euchirella pulchra, 

 Heterochceta ahyssalis, which occur sparingly in the collection, have 

 never before been recorded north of the Mediterranean, this fact 

 indicating a considerable extension of their distribution. 



Calantjs hypeeboeeus Krbyer. 



A number of what I took to be specially large specimens of 

 Calanus finmarchicus were found among the specimens from 20 d. 

 Careful examination clearly proves them to be identical with 

 G. At/per6oreMs, now recognized by Giesbrecht as a distinct species. 

 The nipple-shaped lateral terminations of the cephalothorax, the 

 large first abdominal segment, and the shape and position of the 

 teeth on the basal joint of the 5th feet appear to be the chief points 

 \\ hich separate C. Jiypevhoreus from G. finmarcliicus. Giesbrecht 

 says that joint 19 of the anterior antennse is as long as joints 23 

 and 24 together ; but none of the very few specimens I found with 



Proc. Zool. Soc— 1898, No. XXXVI. 30 



