DISCUSSION OF SPECIES 



209 



Rciniiil(.<. This is the smallest of the Scolccilhricclla species 

 here considered, and may be differentiated hy its size alone. 

 The fifth legs are very different from those of any species 

 hitherto described and furnish the distinguishing character 

 of the species. From the fact that the development stages, as 

 well as the adults, were at the 50-meter level at both stations, 

 it would seem that the species is probably negative to light. 



Genus SCOLECITHRIX Brady, 1883 



Scolecithrix danae (Lubbock) 



\Uiiiiini! danac Lubbock, Trans. Entomol. Soc. London, n. s., 

 \oI. 4, p. 21, pi. 9, figs. 6-9, 1856.] 



This species was very liberally distributed in both oceans 

 e.xcept in the northern regions. It was taken in 8 nocturnal 

 and 8 diurnal surface tows, 80 50-meter tows, and 63 100- 

 meter tows, and in the vertical tow from 1000 meters, station 

 64. It thus shows a definite aversion to light and gives good 

 evidence of migration to the surface at night. 



Genus SPINOCALANUS Giesbrecht, 1888 



Spinocalanus abyssalls Giesbrecht 



\SpniociihiiiiL\ ahyssalis Giesbrecht. Atti R. Accad. Lincei. 

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

 des Golfes von Neapel, vol. ig, p. 209, pi. 13, figs. 42-48; 

 pi. 36, fig. 49, 1S92.] 



Found at three stations in the tropical Atlantic and at 

 many Pacific localities, chiefly in the southeastern region. It 

 was taken in 5 nocturnal and 2 diurnal surface tows, 11 50- 

 meter tows, and 14 loo-meter tows. It is thus negative to 

 light and gives proof of migration to the surface at night. 

 Giesbrecht's original specimens (1888, p. 335) came from 

 the tropical Pacific from depths of 1000 to 4000 meters. 



Spinocalanus caudatus G. O. Sars 



\Spinociihitins ciimhitiii G. O. Sars, Bull. hist, oceanogr. 

 Monaco, no. 377, p. 3, 1920.] 



Not found in the Atlantic plankton, but present in very 

 small numbers in the southeastern and central Pacific. It was 

 taken in i nocturnal and r diurnal surface tow, 3 50-meter 

 tows, and 2 loo-nicter tows. These few specimens preferred 

 the two deeper tows, and one of them had come to the 

 surface at night. 



Spinocalanus magnus Wolfenden 



[Spinocalanus magnus Wolfenden, Jour. Marine Biol. Assoc, 

 n. s., vol. 7, p. 118, 1904.] 



Not found in the Atlantic plankton, but captured at five 

 localities in the central Pacific. It was taken in i nocturnal 

 surface tow, 2 50-meter tows, and i loo-meter tow. The 

 number of specimens in the loo-meter tow was larger than 

 that in the other foiir combined. Wolfenden's (1904, p. 118) 

 original specimens came from the North .Atlantic, and he 

 afterward found the same species in the Gauss plankton 

 from the .Antarctic. 



Genus TEMORA Baird, 1850 



Temora discaudata Giesbrecht 



(Figures 115, 118) 



[Tcmoia discaudata Giesbrecht, Atti R. .Accad. Lincei, Rome, 

 ser. 4, vol. 5, seni. r, p. 814, 1889; Fauna und Flora des 

 Golfes von Neapel, vol. ig, pp. 328, 338, pi. 17, figs. 3, 20, 

 23; pi. 38, figs. 24, 25, 28, 1892.] 



Not found in the Adantic plankton, and in the Pacific 

 confined chiefly to the eastern and southeastern regions. It 

 was taken in 3 nocturnal and 13 diurnal surface tows, 7 50- 

 meter tows, and 10 loo-meter tows. This distribution in- 

 dicates more or less indifference to light, with a slight 

 preference for the surface. The strongly asymmetrical caudal 

 rami are the chief specific characteristics. 



Temora longicornis (Miiller) 



[Cyclops longicornis O. Fr. Miiller, Entomostraca, p. 115, pi. 

 ig, figs. 7-g, 1785.] 



More abundant and more widely distributed in the 

 Atlantic plankton than in the Pacific. It was present in 3 

 nocturnal and 6 diurnal surface tows, 6 50-meter tows, and 

 6 loo-meter tows. Excluding the night tows, the vertical 

 distribution is exactly even at the three depths, but the 

 abundance records are somewhat larger in the 50-nieter 

 tows. The caudal rami are much narrower than in the pre- 

 ceding species, and strictly symmetrical. 



Temora stylifera (Dana) 



[Calanus stylijcr Dana, Proc. Amcr. Acad. Arts and Sci., vol. 

 2, p. 13, 1849; U. S. Exploring Exped., 183S-1842 (Wilkes), 

 vol. 14, pt. 2, Crustacea, p. 1058, 1853; pi. 72, fig. g, 1855.] 



Segregated in both oceans at certain localities long dis- 

 tances apart, and more abundant than either of the other two 

 species. It was taken in 2 nocturnal and 14 diurnal surface 

 tows, II 50-meter tows, and 8 lOO-meter tows. It thus shows 

 a slight preference for the surface, but the abundance records 

 at the three depths are practically ecjual. 



Genus TEMOROPIA T. Scott, 1894 



Temoropia mayumbaensis T. Scott 



(Figures 116, 117) 



[Temoropia mayumbaensis T. Scott, Trans. Linn. Soc. London, 

 ser. 2, Zool., vol. 6, pt. i, p. 79, \>\. 8, figs. 48, 4g; pi. 9, figs. 

 1-12, 1894.] 



A few specimens, including both sexes, were found in the 

 loo-meter tow at stations 35 and 152 in the eastern and 

 central Pacific, respectively. This species was originally 

 described by T. Scott (1894, p. 79) from specimens taken in 

 the Gulf of Guinea, but it has been reported from the 

 Pacific by A. Scott (1909, p. 119) and Farran (1929, p. 257). 

 Nearly all the Siboga specimens were obtained in vertical 

 hauls from considerable depths, which suggests that this is a 

 deep-water species, coming above the loo-meter level only 

 occasionally. 



