8 
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 C. simillimus (Giesbrecht) as a different species. 
A third sj)ecies 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 :—- 
] . Cal. propinquus (Brady). 
2. Cal. acutus (Giesbrecht). 
3. Cal. simillimus (Giesbrecht). 
4. Cal. tonsus (Brady). 
* Lat. 46° 46' S. Long. 45° 31' E. 
Lat. 64° 37' S. Long. 85° 49' E. 
Lat. 47° 25' S. Long. 130° 12' E. 
Lat. 35° 41' N. Long. 157° 42' E. 
Lat. 40° 3' S. Long. 132° 58' W. 
Lat. 9° 43' S. Long. 13° 51' W. 
Lat. 3° 10' N. Long. 14° 51' W. 
Lat. 37° 17' S. Long. 53° 52' W. 
Off Kerguelen Island. Brady, loc. cit. 
