PLANKTONIC STUDIES. 619 



with li/y {{). 218). This astonisliiug wealth of phiuktoii was observed 

 in the whole breadth of the Atlantic tropical zone in Au<^nst and Sep- 

 tember, 1873 ; bnt it was not less than that passed by the GhaJlenger 

 on her return in March and April, 187G, in the eastern part of the same 

 region, between Tristan d'Acunha anil Cape Verde. "When the water 

 was calm, an extraordinary snperabnudanee of pelagi(; life appeared at 

 the surface. Osoillatori(c covered the sea for miles, and vast quantities 

 of Badiolaria {GoUozonn) filled the nets" (p. 1)30). With those and 

 other accounts by tlie Ghallengcy^ those of tlie Vettor Plsaril quite agree. 

 " The zone of equatorial calms is out of all proportion rich in organic life. 

 Sometimes the water seems coagulated, jelly-like, even to the touch. 

 It is impossible to describe the quantities of variously colored forms" 

 (8, p. 31). Chierchia enthusiastically describes the wonderful spectacle 

 which the luminous ocean furnishes at night — "a sea of light which ex- 

 tends to the whole horizon" (pp. 32, 53, etc.). The numerous plankton 

 samples which I myself have investigated from the Atlantic tropical 

 zone show for the most part an extraordinarily rich composition, par- 

 ticularly those between Ascension and the Canary Islands {Challenger 

 stations 345 to 353), above all the two equatorial stations 347 and 348, 

 which, like the Canary currents, which I studied for three months at 

 Lanzarote, whose fabulous wealth I have already mentioned, also belong 

 to the region of the tropical trades-drift. 



The quantity and wealth of forms of the plankton in the tropical 

 zone of the Pacific Ocean is not less than in the tropical region of the 

 Atlantic and Indian oceans. In the most diverse parts of this region 

 the Challenger sailed through "thick banks of pelagic animals." 

 Between the Xew Hebrides and New Cruinea "the surface of the water 

 and its deeper levels swarmed with life. All the common tropical 

 forms were found in great abundance. The list of genera of animals 

 was about the same as in the Atlantic tropical region (pi).218, 219), but 

 it showed consiilerable difference in the relative abundance of species''^ 

 (6, p. 521). Among the Philippines the water shoAved "a quite uncom- 

 mon quantity and variety of oceanic surface animals" (p. G02). On 

 the voyage froin the Admiralty Islands to Japan the oceanic "fauna 

 and flora of the surface was everywhere especially rich and varied. 

 In the neighborhood of the equatorial countercurrents, between the 

 equator and the Carolines, ])elagic foraminifera and mollusks were 

 taken in such quantities in the surface net that they surpassed all 

 earlier observ^ations," etc. (p. 738). Oii the voyage throngh. the central 

 jmrt of the tropical Pacific, from llonolnlu to Tahiti, between 20'^^. 

 lat., and 20^ S. hit,, " the catch of tlie tow net was everywhere very 

 rich. The superabundance of organic life in the equatorial current and 

 countercurrent is very noticeable, as well with reference to the number of 

 species as of individuals''^ (p. 770). From this wcniderfully rich region, 

 which of all parts of tlie tropical ocean is farthest removed from all 

 continents, came the absolutely richest plankton samples which I have 



