1903.] PLANKTON OF THE FAEROE CHANNEL. 123 



containing several undoubtedly epiplanktonic species (e. g. Arach- 

 nactis albida), and has been relegated to the " doubtful" category, 

 closure of the net not having taken place at the proper time ; 

 12/ was known to be epiplanktonic, although there was some 

 doubt as to the exact depth at which it had been towed. I have 

 therefore reprinted in the table (pp. 118, 119) the captures of the 

 seven forms which were taken at least six times, sufficiently often 

 to give approximate data for an estimate of their vertical distri- 

 bution. In discussing this question, I gave a short table on 

 p. 546 showing the occurrences of these seven species expressed 

 in percentages of those Epiplankton and Mesoplankton hauls 

 which contained Copepoda ; this can now be amended as follows, 

 omitting the four doubtful hauls from the calculation : 



Total hauls containing Copepoda. 



Epiplankton. Mesoplankton. 



Calanusfinmarcliicus occurred in 83 % and in 



l Eucalanus attenuatus 22 



Euch&ta norvegica 11 



Metridia longa 22 



1 Pleuromma ab dominate 5 



Acartia clausii 33 



Temora longicomis 33 



The amended table is in harmony with the conclusions drawn 

 from the former, as to the vertical distribution of these forms, 

 except in the case of Acartia clausii, the question of which was 

 expressly reserved (op. cit. p. 549). 



Since the publication of Mr. Thompson's report, I found that 

 Dr. R. Norris Wolfenden was making an exhaustive study of the 

 fauna of the Faeroe Channel, and naturally placed my collection 

 at his disposal. He has been kind enough to furnish the following 

 notes on new and other species, with some of which he has 

 already dealt briefly elsewhere 2 . Exact data of depth &c. were 

 riot always available, as by the time that Dr. Wolfenden received 

 the specimens all the epiplankton hauls of a station had in many 

 cases been put together in one bottle, all the mesoplankton hauls 

 in another, for economy of space. 



PLEUROMMA ROBUSTUM Dahl, Zool. Anzeig. v. p. 16 (1893). 



" This is the common Pleuromma of the Faeroe Channel, and 

 was found to be present in considerable numbers in Dr. Fowler's 

 collection, PI. abdominale occurring much more rarely. In these 

 northern latitudes it almost entirely replaces the latter species. 

 It is readily distinguishable by the horseshoe- shaped mass of red 

 pigment which is present in the anterior and inferior portion of 

 the head at the base of the mouth-organs, and in the male by 



1 Dr. Wolfenden points out that as, according to his wide experience, TSucalanns 

 attenuatus is nowhere met with in the Faeroe Channel, unless perhaps quite 

 exceptionally, these figures probably refer to Eucalanus elongatus. Similarly, for 

 the species Pleuromma abdominale should probably be substituted PL robustum. 



2 R. N. Wolfenden : Journ. Marine Bio!. Assoc. (1902), vi. p. 344. 



