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Genus Calanoides Brady, 1883. 
This genus was established by Brapy in the ‘Challenger’ report, for the reception of a 
Calanoid form whose male possessed characters quite distinct from those of Calanus, the most 
important being the prehensile structure of the fifth feet. The exopodites of this pair are three- 
jointed, elongated, and destitute of plumose setae. The endopodites are rudimentary. That of 
the right foot is three-jointed. The left one is reduced to a single small joint. The absence of 
¢, and thus 
plumose setae on the male fifth feet indicate, that they are not adapted for swimming, 
differ from those of typical Ca/anus. The female is of the usual Cadanus type. GIESBRECHT in 
his great work ‘Fauna und Flora des Golfes von Neapel’ and Giesprecut & ScuMeEIL in ‘Das 
Tierreich’, include this genus under Ca/anus. The fifth feet of the male however, are so obviously 
distinct, that its position there is untenable, and it must therefore be restored as a separate 
genus. The presence of a normal fifth pair of feet in the female, indicates that the genus is 
related to Calanus, and not to Pseudocalanus or Euchaeta, as suggested by Brapy. 
No specimens of Calanoides patagoniensis Brady, the type of the genus, were found in 
the ‘Siboga’ collections, but there is so close a resemblance in the structure of the male fifth 
feet of Calanus brevicornts Lubbock, to Cadanozdes, that it has been included under that genus 
in this report. The genus is now represented by two species, one of which occurred in the 
plankton collected by the ‘Siboga’. 
1. Calanoides brevicornis (Lubbock). 
Calanus brevicornis Lubbock, 1856, p. 11, pl. III. 
Calanus brevicornis Giesbrecht, 1893, p. 90, pl. 6, 7, 8. 
Calanus frontalis Dahl, 1894, p. 76. 
Calanus brevicornis Giesbrecht & Schmeil, 1898, p. 16. 
Calanus brevicornis Cleve, 1904, p. 185. 
Calanus brevicornis Sars, 1907 (0), p. 4. 
This species is easily recognised by its conical and slightly crested forehead, and by the 
rather pointed terminations of the last thoracic segment. The female is of the normal Calanus 
type. The fifth pair of feet of the male although not so elongated as in Calanozdes patagonzensis, 
is of a somewhat similar structure to that of Brapy’s species. The endopodites of both rami 
are rudimentary, that of the right side is three-jointed. The left is reduced to one small joint. 
It was noted in collections taken at the following stations. 
Stat. 165, 20 specimens. — Stat. 168. — Stat. 169, I specimen. — Stat. 172, 2 specimens. -—— 
Stat. 185. — Stat. 225, I specimen. — Stat. 230, 5 specimens. — Stat. 276, 3 specimens. 
Calanotdes brevicornis (Lubbock), has previously been recorded from the Atlantic and 
Indian Oceans only. 
Genus Megacalanus Wolfenden, 1904. 
WOLFENDEN 1904 (wrongly quoted as 1905 in Plankton Studies, part I) briefly described a 
very large Calanoid form under the above genus that, was taken in the deep water of the Atlantic, 
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