Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . ecologicalanimal00hess Year: 1937 THE PELAGIAL 235 water molecules. These facts explain numerous features of the dis- tribution of pelagic animals. The radiolarians of the family Challengeridae (Fig. 58) are as- sorted vertically according to size, the smaller ones in the warmer surface waters, the larger ones below. Thus the average sizes in milli- meters of the following forms may be grouped according to depth:13 50-400 m. Challeugeria xiphodon mm. ' strirei ' ' hars
Ecological animal geography; an authorized, rewritten edition based on Tiergeographie auf ockologischer grundlage . ecologicalanimal00hess Year: 1937 THE PELAGIAL 235 water molecules. These facts explain numerous features of the dis- tribution of pelagic animals. The radiolarians of the family Challengeridae (Fig. 58) are as- sorted vertically according to size, the smaller ones in the warmer surface waters, the larger ones below. Thus the average sizes in milli- meters of the following forms may be grouped according to depth:13 50-400 m. Challeugeria xiphodon mm. ' strirei ' ' harsioni ' 400-1500 m. Ch. bethelli mm. ' slogetti ' iizardi ' 1500-5000 m. Pharyngella gaslrula mm. Ch. thomsoni ' naresi The same is true of other radiolarians, for example, Aulacantha scolymantha. This seems like a mechanical sifting, a sinking of the Fig. 59.—The copepod Calanus finmarchicus, X 26. The antenna used as an oar at the left, the maxilla (greatly enlarged), with its bristles, at the right. After St. Brady. animals to the depths at which they can maintain themselves. Numer- ous Metazoa exhibit the same phenomenon; for example, the arrow- worm, Sagitta hexaptera, which inhabits the lighted pelagial, is larger and more mature, the deeper the source of The little fish Cyclothone microdon increases in size with depth, specimens from 500-m. depth averaging 30 mm., from 1500-m. 60 mm., and specimens
Size: 1896px × 1055px
Photo credit: © Bookend / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: archive, book, drawing, historical, history, illustration, image, page, picture, print, reference, vintage
