. A guide to the study of fishes. Fishes; Zoology; Fishes. 486 Suborder Heterosomata always provided with teeth. Among the 500 species of flounders is found the greatest variation in size, ranging in weight from an oiince to 500 poiinds. The species fotond in arctic regions are most degenerate and these have the largest number of ver- tebrae and of fin-rays. The halibut has 50 vertebra (16 +34), the craig-flounder 58, while in Etropus and other tropical forms the number is but 34 (10+24). The common flotinders of intermediate geographical range (Paralichthys dentatus, etc.) show intermediate n
. A guide to the study of fishes. Fishes; Zoology; Fishes. 486 Suborder Heterosomata always provided with teeth. Among the 500 species of flounders is found the greatest variation in size, ranging in weight from an oiince to 500 poiinds. The species fotond in arctic regions are most degenerate and these have the largest number of ver- tebrae and of fin-rays. The halibut has 50 vertebra (16 +34), the craig-flounder 58, while in Etropus and other tropical forms the number is but 34 (10+24). The common flotinders of intermediate geographical range (Paralichthys dentatus, etc.) show intermediate numbers as 40 (10+30). The apparent signifi-. F'o. 432. Pio 433 Fig. 432^—Heterocercal taU of young Trout, Salmo fario Linnsus. (After Parker & Haswell.) Fig. 433.—Homocercal tail of a Flounder, Paralichthys calijornicus. cance of this pecuHar series of fact is given on page 212, Vol. I. It is, perhaps, related to the greater pressure of natural selection m the tropics, showing itself in the better differentiation of the bones and consequently smaller number of the vertebrae. Fossil flounders are very few and give no clue as to the origin of the group. In the Eocene and Miocene are remains which have been referred to Bothus {Rhombus). Bothus minimus is the oldest species known, described by Agassiz from the Eocene of Monte Bolca. In the Miocene are numerous other species of Bothus, as also tubercles referable to Scophthalmus. On the testimony of fossils alone the genus Bothus, or one. 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 original Jordan, David Starr, 1851-1931. New York, H. Holt
Size: 1945px × 1284px
Photo credit: © The Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, booksubjectzo
