DISCUSSION OF SPECIES 



187 



mens of this species obtained in the Sibogii plankton were 

 taken in vertical hauls from considerable depths. 



Farranula curta (Farran) 



\Coiya-llti cm la Farran, Proc. Zool. Soc. London, 191 1, p. 286, 

 pi. 10, figs. 7-1 1 ; pi. II, figs. 1-6, 191 1.] 



Found at four Atlantic localities and fairly common in the 

 southeastern and central Pacific. It was present in 17 noc- 

 turnal and 21 diurnal surface tows, 18, 50-meter tows, and 17 

 loo-meter tows. It was recorded twelve times as abundant 

 and twelve times as common. The species has been recorded 

 previously from the Indian and Pacific oceans, but not from 

 the Atlantic. 



Farranula gibbula (Giesbrecht) 



(Figure 35) 



[Corycaeiis gibbula Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 7, sem. i, p. 4S1, i8gi; Fauna und Flora des 

 Golfes von Neapel, vol. 19, pp. 661, 675, 1892.] 



Not found in the North Atlantic (stations 6 to 14), in the 

 South Pacific (stations 58 to 60), in the eastern tropical 

 Pacific (stations 70 to 76), and in the North Pacific (stations 

 118 to 128), but present everywhere else. It was taken in 22 

 nocturnal and 76 diurnal surface tows, 41 50-meter tows, 

 and 29 100-meter tows. It was recorded twenty-one times as 

 abundant and thirty-eight times as common. As far as is 

 known, the species is here reported from the Atlantic for 

 the first time. 



Farranula gracilis (Dana) 



(Figure 34) 



[Coiyciieiis gracilis Dana, U. S. E.xpioring Exped., 1838-1842 

 (Wilkes), vol. 14, pt. 2. Crustacea, p. 1207, 1853; pi. 85, fig. 

 \a-d, 1855.] 



Found at three .Atlantic localities, and in the Pacific chiefly 

 confined to the southeastern region. It was present in 13 

 nocturnal and 21 diurnal surface tows, ir 50-meter tows, 

 and 14 100-meter tows. It was recorded three times as abun- 

 dant and nine times as common, but on the other hand 

 twenty records were numerals. Farran (1929, p. 296) has 

 reported it as common in the tropical and north temperate 

 Atlantic as well as in the South Pacific. 



Farranula rostrata (Claus) 



[Corvcaeus rostratus Claus, Die freilebenden Copepoden, p. 

 157, pi. 28, 1863.] 



This was the most abundant species next to carinata, and 

 was present in both oceans except in the far north and all 

 but two stations in the extreme south. It was taken in 32 

 nocturnal and 79 diurnal surface tows, 61 50-meter tows, 

 and 61 loo-meter tows. It was recorded forty-five times as 

 abundant and sixty-eight times as common. Like carinata, 

 this species was repeatedly found equally distributed in two 

 or even all three tows at the same time. It was reported by 

 Farran (1929, p. 297) as scarce in the Atlantic but common 

 ofl New Zealand in the South Pacific. 



Genus GAETANUS Giesbrecht, 1888 



Gaetanus armiger Ciiesbrecht 



[Gactaniis armiger Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 4, sem. 2, p. 335, 1888; Fauna und Flora des Golfes 

 von Neapel, vol. 19, pp. 219, 224, pi. 14, figs. 19, 22, 26, 28, 

 29; pi. 36, figs. 2, 4, 1892.] 



Found only in the Pacific, at station 35 in the loo-meter 

 tow and at station 64 in the vertical tow from a depth of 

 1000 meters. In the former a single specimen and in the 

 latter 4 specimens were obtained. This suggests that the 

 species may have been present in other localities but that the 

 regular tows were not deep enough to reach it. However, 

 one of the two specimens obtained in the Siboga plankton 

 was captured at the surface in the daytime. 



Gaetanus kruppii Giesbrecht 



[Cactaniis \riippii Giesbrecht, Mittheil. aus der Zool. Stat, zu 

 Neapel, vol. 16, p. 202, pis. 7, 8, 1903.] 



The identification of the single immature male from the 

 vertical tow from 1000 meters at Pacific station 64 off the 

 coast of Chile (latitude 31° 54' south, longitude 88° 17' 

 west) should perhaps be considered provisional. From the 

 manner in which the haul was made, it is impossible to say 

 at which level the specimen was captured between 1000 

 meters and the surface. Otherwise, this species has previ- 

 ously been recorded from the North and South Atlantic, the 

 Mediterranean, and the Indian Ocean. 



Gaetanus latifrons G. O. Sars 



[Gaetanus latifrons G. O. Sars, Bull. Mus. oceanogr. Monaco, 

 no. 26, p. II, 1905.] 



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

 station 137, and this was the only record for the cruise. The 

 fact that only a single specimen of this species was found in 

 the Siboga plankton, although the majority of the tows 

 started well below 100 meters, would suggest that the species 

 is not abundant anywhere or at any depth. Sars (1925, p. 57) 

 and With (1915, p. 108) have both recorded this species 

 from the North Atlantic as well as from the Pacific Ocean. 



Gaetanus miles Giesbrecht 



[Gaetanus miles Giesbrecht, Atti R. Accad. Lincei, Rome, ser. 

 4, vol. 4, sem. 2, p. 335, 1888; Fauna und Flora des Golfes 

 von Neapel, vol. 19, pp. 219, 224, pi. 14, figs. 21, 24, 25, 27, 

 30; pi. 36, figs. 1,3, 1892.] 



Found at three widely separated Pacific stations, in the 

 loo-meter tow at stations 37 and 152 and in the vertical tow 

 from 1000 meters at station 64. .\s suggested for armiger, 

 this species may have been present elsewhere below the 

 regular tows, as it is known to be well distributed in both 

 oceans. It is easily recognized by the spine on the forehead 

 and the exceptional length of the first antennae. It has also 

 been reported by Sars ( 1925, p. 54) and With (1915, p. 107) 

 from the North Atlantic, and by Cleve (1904, p. 191) from 

 the South Atlantic. 



