202 



COPEPODS OF LAST CRUISE OF CARNEGIE 



Genus PENNELLA Oken, 1816 



Pennella species 



A free-swimming copepodid larva of some Pennelhi species 

 was taken in the 100-meter tow at station 155.. This was very 

 similar to the description and figures of the copepodid larva 

 of Petinella varians given by Wierzejski (1877, p. 572). But 

 so little is known of the development of this genus that 

 specific identification is impossible. 



Genus PHAENNA Claus, 1863 



Phaenna spinifera Claus 



\Phacnna spinifera Claus, Die freilebenden Copepoden, p. 189, 

 pi. 31, figs. 1-7, 1863.] 



This species was well scattered in both oceans, with 

 numerous large gaps in distribution. It was taken in 7 sur- 

 face tows, 22 50-meter tows, and 23 loo-meter tows, and in 

 the vertical tow from 1000 meters, station 64. It is thus 

 negative to strong light, and did not appear in any of the 

 nocturnal surface tows. It is easily recognized in side view 

 by the highly vaulted cephalothora.x and the absence of fifth 

 legs in the female. 



Genus PHYLLOPUS Brady, 1883 



Phyllopus helgae Farran 



(Figure 89) 



[Phyllopus hclgac Farran, Fisheries, Ireland, Sci. Invest, for 

 1906, pt. 2, p. 83, pi. 9, figs. 5, 6, 1908.] 



Three females were obtained in the vertical tow from a 

 depth of 1000 meters at station 6^ in the southeastern Pacific. 

 This is a deep-water species which has been reported by Sars 

 (1925, p. 342) and A. Scott (1909, p. 148) from moderate 

 depths in the western Pacific. It is possible that deeper tows 

 at other stations in the southeastern Pacific would have re- 

 vealed its presence. The Siboga plankton contained a single 

 male and female of this species from a depth of 700 meters. 



Genus PLEUROMAMMA Giesbrecht, 1898 



This genus is easily recognized by the circular pigmented 

 light spot on one side or the other of the first thoracic seg- 

 ment. Its species are all negative to light, and not one of 

 them was found at the surface in the daytime. Furthermore, 

 only one of the species was at all well distributed or abun- 

 dant; the other four were much scattered in location and 

 greatly reduced in numbers. Steucr's (1932; 1933) excellent 

 monograph on this genus shows that each of the species is 

 much more abundant in the Atlantic and Indian oceans than 

 in the Pacific. 



Pleuromamma abdominalis (Lubbock) 



\Duiptomiis cihdominalis Lubbock, Trans. Eiitomol. Soc. Lon- 

 don, n. s., vol. 4, pt, r, p. 22, pi. 10, 1S56.] 



Not found in the Atlantic plankton and at onlv a lew 

 localities in the Pacific, long distances apart. It was taken in 

 2 nocturnal surface tows and 6 loo-meter tows, and in the 



vertical tow from 1000 meters, station 64, but not in any 50- 

 meter tow nor at the surface in the daytime. Although it 

 comes to the surface at night, it descends to 100 meters or 

 more by day and is thus negative to light. Steuer's (1932, 

 p. 9; 1933, p. 5) distribution map shows this species as very 

 abundant in the North Atlantic in deep water. 



Pleuromamma gracilis (Claus) 



[Phinomma gracilis Claus, Die freilebenden Copepoden, p. 

 197, pi. 5, 1863.] 



Found once between stations 13 and 14 in the Atlantic, 

 and widely scattered in the Pacific, with long gaps in distri- 

 bution. It was taken in 12 nocturnal surface tows, 14 50- 

 meter tows, and 30 100-meter tows, and in the vertical tow 

 from 1000 meters at station 64. It was recorded as abundant 

 in the single Atlantic surface tow and once in the Pacific at 

 the surface, and as common three times. Therefore, it mi- 

 grates to the surface in considerable numbers at night, 

 although it was not found there at all during the day. 



Pleuromamma qiiadrungulata (F. Dahl) 



[P/fiiromma quadrungidatiiin F. Dahl, Zool. Anz., vol. 16, no. 

 415, p. 105, 1893.] 



A single female of this species was present in the 100- 

 meter tow at station 49 in the southeastern Pacific, and this 

 was the only record for the cruise. This species was said by 

 Esterly (1912, p. 315) to be "rather common in all the deeper 

 hauls' off the California coast at San Diego. But he added, 

 "none taken above 170 fathoms." This suggests that, having 

 been found in the southeastern Pacific, it may be more com- 

 mon there below 100 meters than would be inferred from 

 this single specimen. Steuer's (1932, p. 26; 1933, p. 14) 

 distribution map shows this species to be distinctly tropical 

 in habitat. 



Pleuromamma robusta (F. Dahl) 

 (Figure 98) 



[Plciiromma robustum F. Dahl, Zool. Anz., vol. 16, no. 415, 

 p. 105, 1893.] 



Three specimens of this species were taken in the vertical 

 tow from a depth of 1000 meters at station 64, and it was 

 found in the loo-meter tows at six other Pacific stations. A 

 few individuals also occurred in one 50-meter tow, but none 

 were found at the surface either by day or by night. This 

 species has been reported by Farran (1929, p. 260) as com- 

 mon in a small area south of New Zealand in the Pacific. 

 Steuer (1932, p. 20; 1933, p. 11) recorded it from the Ant- 

 arctic south of Africa, but as much more abundant in the 

 tropical and northern Atlantic. 



Pleuromamma xiphias (Giesbrecht) 



{rlcuromma xiphias Giesbrecht, Atti R. Accad. Lincei, Rome, 

 ser. 4, vol. 5, sein. 2, p. 25, 1889; Fauna unci Flora des Golfes 

 von Neapel, vol. 19, p|i. 347, 357, pi. 32, fig. 14; pi. 33, figs. 

 42, 45, 50, 1892.1 



Taken in a nocturnal surface tow between stations 20 and 

 21 in the Atlantic, and in the vertical tow from a depth of 



