. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 196 THREE CRUISES OF THE " Fig. 124. — Hastigerina pelagica. (Clialleiiger.) tigerina (Fig. 124), are pelagic, there is a host of other are- naceous forms, perhaps the majority of the fora- minifera, which certainly live at the bottom. Both the pelagic and bottom spe- cies form a most impor- tant factor in the food sup- ply of the abyssal fauna. The modern greensand found along the edge of the Gulf Stream proves that multitudes of dead tests constantly drop from the surface, and when they reach b
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology; Zoology. 196 THREE CRUISES OF THE " Fig. 124. — Hastigerina pelagica. (Clialleiiger.) tigerina (Fig. 124), are pelagic, there is a host of other are- naceous forms, perhaps the majority of the fora- minifera, which certainly live at the bottom. Both the pelagic and bottom spe- cies form a most impor- tant factor in the food sup- ply of the abyssal fauna. The modern greensand found along the edge of the Gulf Stream proves that multitudes of dead tests constantly drop from the surface, and when they reach bottom, they still contain a suf- ficient amount of sarcode to make an excellent meal for some abyssal echinoderms. The species that live on the bottom, and in some localities must thickly cover its surface, afford excellent feedingf- - orounds for the dwellers of these depths. With the thousands of radiolarians and other pelagic globigerinse occur minute protozoa, their capacity for floating being increased by the huge spines or extensile pseudopodia which they stretch out in every direction. The depth at which so-called pelagic foraminifera have been found depends upon the fact that, during rough weather or under unsuitable cir- cumstances, they sink to a considerable depth, and, while they would strictly come within the definition of pelagic animals, they may thus frequently be found living apparently on the bottom. One of the most common of the pelagic protozoa is a spe- cies of the genus Noctiluca. (Fig. 125.) On favorable nights it forms a thin sheet of phosphorescence, as it were, spread over the sea. The tow-net, when dragged during the night, reveals the phosphorescent color characteristic of different groups, and one who is accustomed to such nocturnal pelagic. Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the orig
Size: 1406px × 1778px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorha, bookcentury1800, bookdecade1860, booksubjectzoology
