G02 REPORT OF COMMISSIONER OK FI8JI AND FISHERIES. 



yellowish or reddish ''iiuiiual miisli," eoiiiposcd in b}- far tlie j^reater 

 part of copepods. In the journal whieh I kept in the winter of 18()G-(i7, 

 at Lanzarote, in the Canary Islands, of the varying constitution of tlie 

 plankton, for many days there is only the remark: ''almost pure buck- 

 ets of copepods," or " the collection consisted almost entirely of Crus- 

 tacea, by far the greater part of copei)ods." That these small crus- 

 taceans form the cliief food supi)ly for many of the most important 

 food-fishes {c. //., the lierring) has long been known. In the Arctic as well 

 as the Antarctic Ocean Calanus Jinmarchicus and a few related species 

 form in general the chief bulk of the plankton, and furnish food for 

 pteropods and cephulopods, for the divers and ])enguins, for many fishes 

 and whales. On the voyage from Japan to Honolulu the Challenger 

 sailed through M'ide stretches of the ISTorth Pacific Ocean which were 

 covered with red and white patches, caused by great accumulations of 

 two species of small copepods, the red being CaUmus pro2)i)iquus (8, p. 

 758). In many other regions, from the Polar Circle to the Equator, the 

 ship passed through white bands many miles wide, comi^osed solely 

 of (iopepods (8, p. 843). That their appearance is very irregular and 

 dependent on many conditions is true of this very imjiortant group 

 of plankton animals as for all others. For two days the Challenger went 

 through thick shoals of CoryeaeuH peUneidu^. For the next three days 

 the copepods had entirely disappeared. 



Ilensen has made statistical statements upon the appearance of the 

 copepods of the North and Baltic seas (9, p. 45). Chun has lately shown 

 that this order plays a highly significant role, not only at the surface, 

 but also at considerable depths (000 to 1,300 meters), (15, p. 25). "Their 

 abundance and richness in forms in greater depths is absolutely aston- 

 ishing. Larval forms of species sessile or living ui)on the bottom min- 

 gle in confusion with the young forms and sexually mature stages of 

 eupelagic species. Many species hitherto regarded as varieties are 

 numerously rcpi'esented in the dei)ths." On the other hand, the order 

 seems to be very poorly rei)resented at very great depths. T\iq Chal- 

 lenger found only one very characteristic deep-sea species in 2,200 

 fathoms — Pontostratioides ahj/ssieolki (8, ]). 845). Some genera never 

 leave the surface; and arc antopelagic, e.g., Fontellina (15, p. 27). 



Ostraeoda. — The ostraeods are, next to the copepods, the most impor- 

 tant Crufitaeca of the i)lankton, and are represented at the surface as 

 well as in different dei)ths by nnisses of many species. In the (ecology 

 of the ocean they play a similar role, as do the near-related cladocerans 

 {DaphnUhv) in the fresh water. The Challenger collected 221 species of 

 ostracixls. Of these 52 were found below 500 fathoms, 19 below 1,500, 

 and 8 below 2,00() fathoms in depth. INlany ostraeods, like many cope- 

 pods and other crustaceans, belong to the most important luminous 

 animals of the ocean. On my journey to ('eylon (in the beginning of 

 November, 1881), as well as on the return trip (middle of March, 1882),- 

 J admired as never before the oceanic light in its splendor. "The whole 

 ocean, so far as the eye could reach, was a continuous shimmering sea 



