DISCUSSION OF SPECIES 



171 



only rccorJ for the entire cruise. All the specimens thus far 

 obtained have been deep-water captures and probably this 

 copepod does not get into the upper 100 meters during the 

 daytime. The species is distinguished by a very large sense 

 organ at the tip of the second maxilla and by the structure 

 of the fifth legs. 



Genus AMALLOTHRIX G. O. Sars, 1925 



Chart 2. Daytime vertical distribution of certain species of 

 AmaUotluix: (i) tiiciiatii, (2) obtiisifrons, (3) propinqiia. 



Amallothrix arcuata (G. O. Sars) 



(Figures 5, 131) 



[ScohclthiiccUii arcuata G. O. Sars, Bull. Inst, oceanogr. 

 Monaco, no. 377, p. 10, 1920.] 



Three females of this species were taken from the 100- 

 meter tow at station 35 off the Pacific end of the Panama 

 Canal, and this was the only record for the cruise. It may be 

 recognized by the strong curve of the frontal margin in 

 lateral view and by the structure of the fifth legs. The species 

 was reported by Sars (1925, p. 185) from the North Atlantic 

 off the west coast of Scotland. This is the first record from 

 the Pacific Ocean. 



Amallothrix obtusifrons (G. O. Sars) 

 (Figure 128) 



[Amallophora obtusifrons G. O. Sars, Bull. Mus. oceanogr. 

 Monaco, no. 26, p. 11, 1905.] 



Not found in the Atlantic plankton, but present at four 

 stations in the eastern Pacific and one in the central region. 

 It was taken in 3 50-meter tows and 2 loo-meter tows, but 

 did not appear at the surface either by day or by night. It is 

 probably negative to light, but gave no evidence of nocturnal 

 migration. All the Siboga specimens were taken in vertical 

 hauls from depths of 1000 to 1500 meters and none at the 

 surface.' 



Amallothrix propinqua (G. O. Sars) 

 (Figure 123) 



[Scolccit/iriccHa propinqua G. O. Sars, Bull. Inst, oceanogr. 

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



Not present in the Atlantic plankton, but present at one 

 station in the eastern and four in the central tropical Pacific 

 near the Samoan Islands. It was taken in i daytime surface 

 tow, I 50-meter tow, and 3 100-meter tows. The total num- 

 ber of specimens was very small, and only one of them was 



' There is some question whether the data here given apply to 

 this species or to Scolecithricella obtusifrons, which does not 

 appear in this report. Since the author is deceased, it is not now 

 possible to clear up the matter. — Ed. 



found at the surface. The species was reported by Sars (1925, 

 p. 178) from the temperate Atlantic, but these are the first 

 records from the Pacific. 



Amallothrix valida (Farran) 



(Figures 7, 129) 



[Scolccit/irix valida Farran, Fisheries, Ireland, Sci. Invest, for 

 1906, pt. 2, p. 55, pi. 5, figs. 14-17; pi. 6, fig. 7, 1908.] 



Two females were taken in the vertical tow from a depth 

 of 1000 meters at station 64 in the southeastern region of the 

 Pacific, and this is the only record for the cruise. Farran 

 (1908^, p. 55) originally obtained the species from deep 

 water off the west coast of Ireland, and it was present in two 

 vertical tows of the Siboga plankton, one from 1000 and the 

 other from 2000 meters. It would seem, therefore, that this 

 is a deep-water species which usually keeps below the 100- 

 meter level in the daytime. 



Genus ANOMALOCERA Templeton, 1837 



Anomalocera patersonii Templeton 



(Figure 8) 



[Anomalocera patersonii Templeton, Trans. Entomol. See. 

 London, vol. 2, pt. i, p. 35, pi. 5, 1837.] 



This large and brilliantly colored species was found at two 

 stations (9, 10) in the North Atlantic south of Greenland, 

 and at two (113, 158) in the Pacific, the first off the coast of 

 Japan and the second about 1000 miles northeast of the 

 Samoan Islands. Except for a single specimen listed for the 

 1 00-meter tow only at station 113, all the Carnegie records 

 for the species were made with surface nets. This individual 

 may have slipped into the net at a higher level as it was 

 being lifted. Since this species has never been reported except 

 at the surface, it can be regarded as strongly positive to light. 

 Like Calanus finmarchiau, it has sometimes been found in 

 great shoals at or close to the surface, but no trace of any- 

 thing of that sort occurred in the Carnegie plankton. 



Genus ARIETELLUS Giesbrecht, 1892 



Arietellus setosus Giesbrecht 



(Figures 3, 4) 



[Arietellus setosus Giesbrecht, Fauna und Flora des Golfes von 

 Neapel, vol. 19, p. 415, pi. 29, figs, i, 3-7, 9-13, 21; pi. 39, 

 figs. 34-36, 1892.] 



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

 100-meter tow at station 42, and this was the only record for 

 the cruise. The species has been reported by Esterly (1911, 

 p. 335) from the San Diego region, California, and he men- 

 tioned the rose color of the numerous setae from which the 

 specific name is derived. This color was still very prominent 

 in the Carnegie specimens after four years of preservation. 



Genus AUGAPTILUS Giesbrecht, 1889 



Augaptilus longicaudatus (Claus) 



[Hemicalanus longicaudatus Claus, Die freilebenden Cope- 

 poden, p. 129, pi. 29, 1863.] 



