i8o 



COPEPODS OF LAST CRUISE OF CARNEGIE 



Chart 6. Daytime vertical distribution of species of Corycaeus: 

 (i) agilis, (2) andrewsi, (3) angUciis, (4) catus, (5) dausi, (6) 

 crasshisciiltts, (7) diibiiis, (8) flaccus, (9) jurcijer, (10) ^/'«- 

 brechti, (11) laiitus, (12) Umbatus, (13) longistylis, (14) /z/i?'- 

 bockji, (15) minimus, (16) ovalis, (17) pacificus, (18) ptimihis, 

 (19) robiistus, (20) speciosiis, (21) typicus. Each species was 

 found somewhere at each of the three depths. Seven were least 

 abundant in the 100-meter tow, more abundant in the 50-meter 

 tow, and most abundant at the surface. Five were just the re- 

 verse, least abundant at the surface and most abundant in the 

 loo-meter tow. Six were most abundant in the 50-meter tow and 

 less abundant in the other two tows; two were least abundant in 

 the 50-meter tow, and one was equally abundant in all three tows. 



Corycaeus anglicus Lubbock 



(Figure 43) 



[Corycaeus anglicus Lubbock, Ann. and Mag. Nat. Hist., ser. 2, 

 vol. 20, p. 408, pi. II, figs. 14-17, 1857.] 



Found at five localities in the western and Caribbean re- 

 gions of the Atlantic and at ten stations in the Pacific, chiefly 

 in the central part. It was present in 9 surface tows, 4 50- 

 meter tows, and 3 lOO-meter tows. It has been taken hitherto 

 chiefly in the northern Atlantic, and has been pronounced by 

 Bars in his Crustacea of Norway (1918, p. 196) "a pro- 

 nouncedly pelagic animal, which has its true home in the 

 open sea and only quite accidentally is thrown by the currents 

 nearer to the shores." From these Carnegie records it would 

 seem to prefer the surface rather than the greater depths, and 

 this agrees with the statements of other observers. 



Corycaeus catus F. Dahl 



[Corycaeus catus F. Dahl, Verhandl. Deut. zool. Gesellsch., 

 vol. 4, Miinchen, p. 72, 1894/).] 



This species was not present in the Atlantic plankton, but 

 was widely scattered over the Pacific, with large gaps in the 

 distribution. It was taken 19 times in the loo-meter tow, 17 

 times in the 50-meter tow, and 14 times at the surface in the 

 daytime and 9 times at night. It thus shows a slight prefer- 

 ence for the greater depths during the day, but migrates 

 rather regularly to the surface at night. Only the females of 

 the species were known at first, and its validity was in doubt, 

 but the descriptions and figures of both se.xes by Maria Dahl 

 (1912, p. 99) fully established it. 



Corycaeus clausi F. Dahl 



(Figure 42) 



[Corycaeus clausi F. Dahl, Verhandl. Deut. zool. Gesellsch., 

 vol. 4, Miinchen, p. 73, 1894^.] 



This species was present twice in the Atlantic plankton, 

 one of the localities being a nocturnal surface tow; it was also 

 taken in 3 nocturnal surface tows in the Pacific. In the day- 

 time it was found in 8 surface tows, 4 50-meter tows, and 2 

 loo-meter tows. It is evidently not abundant anywhere, and 

 in these few Carnegie records showed a preference for the 

 surface rather than for the deeper tows. From the records of 

 other investigators it would seem to be more of an Atlantic 

 than a Pacific form. 



Corycaeus crassiusculus Dana 



[Corycaeus crassiusculus Dana, Proc. Amer. Acad. Arts and 

 Sci., vol. 2, p. 36, 1849; U. S. Exploring Exped., 1838-1842 

 (Wilkes), vol. 14, pt. 2, p. 1214, 1853; pi. 85, fig. 7, 1855.] 



This is the most widely distributed and most abundant 

 species of the genus, and was found everywhere in both 

 oceans except in the far north and in the four southernmost 

 stations of the Pacific. It was taken in 16 nocturnal and 84 

 diurnal surface tows, 103 50-meter tows, and 77 loo-meter 

 tows, and was frequently found in all three tows at the same 

 station. These records indicate more or less indifference to 

 light, with a moderate preference for the 50-meter tow. Dana 

 (1849, pp. 36, 38; 1853, pp. 1214, 1222) originally described 

 a male, crassiusculus, and a female, venustus, in the same 

 paper, and these have since been identified as the two sexes of 

 the same species. Hence the name of the male, described first, 

 must be taken for both sexes, and the name of the female 

 dropped. 



Corycaeus dubius Farran 

 (Figure 40) 



[Corycaeus dubius Farran, Proc. Zool. Soc. London, 191 1, pp. 

 292-294, pi. 12, fig. 7; pi. 14, figs. 5-9, 191 1.] 



Found at four stations in the middle and Caribbean regions 

 of the Atlantic and widely scattered over the Pacific. But the 

 gaps in its distribution are so numerous that it was scarcely 

 found anywhere at two stations in succession. It was captured 

 in 19 surface tows, 12 50-meter tows, and 5 loo-meter tows. 

 These records show a preference for the two upper tows, 

 especially for the surface tow, but the species was not present 

 in any of the nocturnal surface tows. Originally founded 

 somewhat doubtfully, as its name suggests, on a single female. 



