DISCUSSION OF SPECIES 



175 



Candacia falcifera Farran 



(Figure 13) 



[Caniiacia falcifera Farran, British Antarctic (Terra No\'a) 

 Exped., pt. 10, Zool., vol. S, no. 3, p. 270, fig. 28, ig^g.] 



Two females were obtained from the 100-meter tow at 

 station 23 in the tropical Atlantic, and this was the only 

 record for the cruise. Although the species was established by 

 Farran ( 1929, p. 270) on specimens obtained by the Terra 

 Nova expedition in the Antarctic south of New Zealand, 

 these 2 tropical Atlantic specimens show exactly the same 

 characteristics, especially as regards the fifth legs (fig. 13). 



Candacia longimana (Claus) 



(Figure 26) 



\Candace longimana Claus, Die freilebenden Copepoden, p. 

 140, pi. 27, 1863.] 



Not found in the Atlantic plankton but widely and very 

 irregularly dispersed in the eastern, central, and western 

 Pacific within the tropics. It was taken in 2 surface tows, 3 

 5o-meter tows, and 9 loo-meter tows, and in every instance 

 the abundance record was 5 or less. The small, curved, and 

 shriveled spine at the right posterior corner of the fifth 

 thoracic segment is a good character for identifying the 

 species. 



Candacia norvegica (Boeck) 

 (Figure 6) 



[Candace iiori'cgica Boeck, Forhandl. Vidensk. Selsk. Chris- 

 tiania, p. 235, 1865.] 



Found near latitude 40° in the western part of the North 

 Atlantic, in the Sargasso and Caribbean regions, and in the 

 eastern, central, and western Pacific. It was present in 12 

 nocturnal and 4 diurnal surface tows. 22 50-meter tows, and 

 15 loo-meter tows. It thus preferred the two deeper tows 

 during the daytime but migrated frequently to the surface 

 at night. 



Candacia pachydactyla (Dana) 

 (Figure 15) 



[Candace pachydactyla Dana, Proc. Amer. Acad. Arts and 

 Sci., vol. 2, p. 23, 1849; U. S. Exploring Exped., 1838-1842 

 (Wilkes), vol. 14, pt. 2, Crustacea, p. 1113, 1S53; pi. 78, figs. 

 2a, b, 3(7, b, 4a-c, 1855.I 



Found in the central and Caribbean regions of the Atlantic 

 and chiefly in the eastern part of the Pacific. It was taken in 

 2 nocturnal and 3 diurnal surface tows, 9 50-meter tows, and 

 7 loo-meter tows, but the number of specimens was too 

 small for any general statement. A. Scott (1909. p. 153) 

 listed it as moderately common in the Siboga plankton and 

 stated that it was widely distributed in tropical seas. The 

 Carnegie records would probably have been more numerous 

 had the tows been taken below 100 meters. 



Candacia simplex (Giesbrecht) 



(Figures 16, 17) 



\CanJacc simplex Giesbrecht, Atti R. Accad. Lincei, Rome, ser. 

 4, vol. 5, sem. I, p. 815, 1889; Fauna und Flora des Golfes 



von Neapcl, vol. 19, pp. 424, 440, pi. 21, figs. 10, 21, 25, 30, 

 31; pi. 22, figs. 21, 29; pi. 39, fig.s. 3, 14, 1892.] 



This was the most widely distributed of all the Candacia 

 species in both oceans, especially in the Pacific, where it was 

 found in every region except the extreme north. It was taken 

 in 16 nocturnal and 32 diurnal surface tows, 73 50-meter 

 tows, and 58 loo-meter tows. In the daytime, therefore, it 

 was more often present in the deeper tows, especially at 50 

 meters. But it was frecjuently equally distributed in all three 

 tows at the same time, and was seldom restricted to a single 

 depth. Wherever it retnains during the day, it evidently 

 migrates regularly to the surface at night, since it appeared 

 in so many of the nocturnal tows. 



Candacia tenuimana (Giesbrecht) 



[Candace tenuimana Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 5, sem. i, p. 814, 1889; Fauna und Flora des Golfes 

 von Neapel, vol. 19, pp. 424, 439, pi. 21, figs. 8, 28, 29; pi. 

 22, figs. 2, 30, 37, 1892.] 



A single female was captured in the loo-meter tow at 

 station 115 ofT the Japan coast in the Pacific, and this was the 

 only record. The Sihoga plankton yielded 2 specimens in a 

 vertical haul from a depth of 1500 meters. This suggests not 

 only that the species is rare, but also that it is more likely to 

 be found in the depths below the 100-meter level. It has been 

 reported from the South Atlantic by Cleve (1904, p. 187) 

 and from the western Mediterranean and the tropical Pacific 

 by Giesbrecht (1898, p. 128). 



Candacia truncata (Dana) 



(Figure 11) 



[Candace truncata Dana, Proc. Amer. Acad. Arts and Sci., vol. 

 2, p. 24, 1849; U. S. Exploring Exped., 1838-1842 (Wilkes), 

 vol. 14, pt". 2, Crustacea, p. 11 18, 1853; pi. 78, fig. %a-d, 1855.] 



This species was not found in the Atlantic plankton, but 

 was well distributed in the eastern and western Pacific and 

 lacking in the northern part. It was found in 3 nocturnal and 

 I diurnal surface tows, 24 50-meter tows, and 25 loo-meter 

 tows. In the daytime, therefore, it was practically confined to 

 the two deeper levels, but at night it migrated occasionally to 

 the surface. In the Siboga plankton it was found in 33 of the 

 surface tows, 10 of which were nocturnal, and in 7 vertical 

 tows from considerable depths. 



Candacia varicans (Giesbrecht) 



[Candace varicans Giesbreclit, Fauna und Flora des Golfes von 

 Neapel, vol. ig, pp. 424, 439, pi. 21, figs. 3, 4, 11, 24; pi. 22, 

 figs. 10, 25; pi. 39, figs. 2, 23, 1892.] 



Found in the tropical region of the Atlantic and in the 

 western Pacific; entirely confined to the two deeper levels, 

 appearing in 5 50-meter tows and 9 loo-meter tows. It was 

 obtained originally by Giesbrecht (1892, p. 424) from the 

 Mediterranean, but has been reported from the North 

 Atlantic and the South Pacific, off the New Zealand coast. 

 The structure of the fifth legs, especially those of the male, 

 furnishes a ready means of identifying the species. 



