4 o 



COPEPODA 



25 is 2 - i as long as the 24 and n as long as the 23. The Le as well as the Re of the maxillulae 

 have only n setae. The distal setae of the maxillae show indication of the curious structure found 

 in the full-grown. The pes I III have the Ri II <^ III and the Re II<v>HI fused; the Re II <v> III pes 

 II has 3 Se and 5 Si; the Re II 03 III pes III has only 2 Se; and its Ri has 8 setae. The pes IV 

 has Ri I co III fused with 7 setae and the Re I cc III has 3 Se and 3 Si. The fifth pair of legs is, as 

 shown in Cal. jinmarchicus, quite rudimentary. In contrast to the full-grown female a distinct pore 

 was found at the base of Se hasp. Ill of the pes II III; in addition to this a pore was found at the 

 base of Se Re I and Se 3 Re III. 



Occurrence. This species has not been captured by the Ingolf Expedition, but the Thor 

 Expedition has taken it from the following stations 1904 and 1905. 



Thor '9/ 6 1904 St. 152 65oo Lat. N. 28oi Long. W. Yt. 1000 M. Wire 2 f ?. 



'/ 7 1905 St. 180 6i34 Lat. N. i9O5 Long. W. Yt. 1800 M. Wire 3 f ?. 



"/ 7 1904 St 183 6i30 Lat. N. I7o8 Long. W. Yt. 1803 M. Wire 4 f?; ay (V); 2 (III). 



2 5/ 5 1904 St 104 6a47 Lat. N. I5O3 Long. W. Yt. 1500 M. Wire i f ?. 



22 / 5 1904 St. 99 6ii5 Lat. N. 935 Long. W. Yt. 1700 M. Wire if?. 



7/ 6 1905 St. 71 5747 Lat N. n33 Long. W. Yt. 1500 M. Wire 2 f?. 



% 1905 St. 72 5752 Lat. N. 953 Long. W. Yt. 1500 M. Wire 2 f?. 



"/ 9 1905 St 167 5746 Lat. N. 9 55 Long. W. Yt. 1500 M. Wire 3 f?. 



Distribution. This species has previously only been recorded from the great depths in the 

 Atlantic Ocean viz. from the west coast of Ireland as far north as 55 Lat. North, from the North 

 Atlantic (c. 40 Lat. N. 70 Long. W.) and the Mid Atlantic (c. 10 Lat. N. and 20 Long. W.). As it 

 has not been taken by the Siboga Exp., it is rather doubtful if it is found in the Indian Ocean. 



Remarks. It seems to me scarcely doubtful, that the described species is identical with Brady's 

 Calanus princeps ; this author writes: The abdomen is short, stout and three-jointed. The latter character 

 is certainly due to a mistake. His fig. 5 of the maxillula shows, probably wrongly, only 6 setae in Le 

 I and 10 in Re. As I have examined specimens, identified by Sars, it is scarcely doubtful that the 

 species is identical with Sars and Farran's Megacalanus princeps Brady. Farran has suggested, that 

 Wolfenden's Heterocalanus medius is identical with Cal, princeps Brady, and I think he is right. My 

 specimens differ from Wolfenden's fairly exhaustive description (1906 p. 27) in the following features: 

 i) Le I maxillulae has 9 instead of 7 bristles and the 2 setae of basp. II are not "very short and 

 delicate". 2) the Se Re III pes I is placed nearer the base than the tip. 



Megacalanus Wolfenden. 



1904. Megacalanus, Wolfenden 1908. Megacalanus pars, Farran, p. 21. 



1905. Macrocalanus pars, G. O. Sars. I99- Megacalanus, Scott, pp. 10 12. 



1905. Megacalanus pars, Wolfenden. ' 1911. Megacalauus, Wolfenden, pp. 195 196. 



1906. Megacalanus pars, Pearson, p. 6. [ 



The type of this genus, which is probably more related to Calanus than Macrocalanus and 

 Bathycalanus, is M. princeps \ it is well characterized by its size and the curious hook on the anterior 



