244
THE BIOLOGY OF FISHES
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distribution with apparently no means of com—,
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munication between the different members of the
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As an example of this kind we have the large family of .
Pipe—shes (Syngnathidæ and related forms), for the most
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part coastal forms in all parts of the world with not a few
living in fresh water. Regarding these Duncker gives the
following information. Nerophina belongs exclusively to
the North—East Atlantic ;
the freshwater Doryichthys,
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Cœlonotus, and Belonichthys are ;lndo—Pacicforms,
uviatilis occurs in the Zambesi, in
gascar, Celebes, and the Philippines ; Microphis is
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Indd—Pacic also, but M. lineatus and M. aculeatus, nearly
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related forms, occur in the mouths of rivers in the Atlantic,
the former in Central and South America, the latter on the
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African side fr0m Senegambia to Portuguese Congo; the
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genus Leptonotus again occurs on the west coast of America,
in New Zealand, Tasmania, Australia, and the Fiji Islands,
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whilst the Pegasus family occurs in China, japan, the
Archipelago, and Aimtralia.
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These are all forms of Tertiary or more recent origin,
and thewide distribution may have been effected in part
through drifting_seaweed to Which they c-anattach themselves,
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as in the Sargasso Sea, but we can hardly accept this explana—
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tion for all cases.
It is more probable that they have come
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from some pelagic and related forms of Wide
such as the Flute-mouths, Fistularia, which is common to
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the tropical andsubtropical waters of the Atlantic and Indo—
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Pacicand which is
represented in thèlàter—fCenozoic
depositsàofj Europe.- As shown in Chapter V, Fistularia
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the characters of a Clupeid 'larva, and We
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thus bbtai‘n ano‘thei‘; 'good eXample‘ofjthe transformation of
the pelagic,ffee—sWitnming type into a diversity of sedentary, - '
coastal, orfteshwéiterforms_
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With regard to the distribution of more
.shes
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since the Tertiary period, we nd in C. TateRegan’s book
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on the British Freshwater Fishes an interesting
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“of
and'fro of Ï theshpopulatiOn off_Ïthese _' '
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,iSlands Twith5the
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