R. NORRIS WOLFENDEN. 



C. simillimus. Giesbrecht also suggests that the similarity between the two species 

 leads to the doubt whether C. propinquus has such a wide distribution as Brady 

 imagined. This author gave it a distribution throughout all oceans in the southern 

 Indian, north in the Pacific (to 35 N.), and in the Atlantic to 30 N.* 



I have made a careful examination of dissected specimens from the following 



localities : 



Lat.' 56 31' S. Long. 156 19' 30" E. 



Lat. 59 19' S. Long. 124 24' 30" W. (28. vi. 04). 

 Lat. 84 01' S. Long. 170 49' E. 

 Lat. 58 49' 45" S. Long. 154 48' W. (24. vi. 04). 

 Lat. 50 48' S. Long. 170 2' E. 



and in these hauls occur many examples of a Calanus which answers in all particulars 

 to Giesbrecht's C. simillimus. As these have well-developed genital segments, in some 

 cases with spermatophores attached, and differ from C. propinquus not only in size, 

 being very much smaller than this species, but also in the proportions of the third and 

 fourth pairs of feet, and the serration and proportions of the fifth pair, there is no doubt 

 that this entirely agrees with the animal briefly described by Giesbrecht ; and I think 

 he is correct in regarding it as a species different from C. propinquus, and that the 

 distribution of the latter is not so extensive as was imagined by Brady. I therefore 

 describe (7. simillimus (Giesbrecht) as a different species. 



A third species of Calanus which does not agree with either of these, being 

 altogether less robust than C. propinquus, and constantly much smaller, but at the 

 same time larger than simillimus, but with the basals of the fifth pair without any 

 marginal teeth, and the distal margins of the basals of the second to fourth pairs 

 with a row of spines, may probably be C. tonsus (Brady), but the description given 

 by this author is of the briefest character, and he gives only two figures, which do 

 not assist in the identification. However, I attach to it Brady's name, as it is probably 

 the animal meant by Brady. 



Four species of Calanus are found in the ' Discovery ' collection : 



1. Cal. propinquus (Brady). 



2. Cal. acutus (Giesbrecht). 



3. Cal. simillimus (Giesbrecht). 



4. Cal. tonsus (Brady). 



* Lat. 46 46' 8. Long. 45 81' E. 

 Lat. 64 87' S. Long. 85 49' E. 

 Lat. 47 25' 8. Long. 180 12' E. 

 Lat. 85 41' N. Long. 157 42' E. 

 Lat. 40 3' 8. Long. 132 58' W. 

 Lat. 9 48' S. Long. 18 51' W. 

 Lat. 8 10' N. Long. 14 51' W. 

 Lat. 87 17' S. Long. 53 52' W. 

 Off Kcrguelen Island. Brady, loc. cit. 



