. An introduction to zoology : for the use of high schools . eal bones are well provided therewith. On the roof of themouth in front of the first gill there is a rudimentary fifth gillcalled a pseudobranch, through which only arterial blood5 58 HIGH SCHOOL ZOOLOGY. circulates; its meaning will afterwards be explained. Thisfamily is characteristically a fresh-water one, the section of theCatosomidae being nearly confined to North America, and in-cluding our suckers, lake-mullet (Fig. 23), carp and carp-suckers,while the rest of the Cyprinoids are abundantly represented inthe Old World as well a
. An introduction to zoology : for the use of high schools . eal bones are well provided therewith. On the roof of themouth in front of the first gill there is a rudimentary fifth gillcalled a pseudobranch, through which only arterial blood5 58 HIGH SCHOOL ZOOLOGY. circulates; its meaning will afterwards be explained. Thisfamily is characteristically a fresh-water one, the section of theCatosomidae being nearly confined to North America, and in-cluding our suckers, lake-mullet (Fig. 23), carp and carp-suckers,while the rest of the Cyprinoids are abundantly represented inthe Old World as well as the New. The suckers and their alliesattain a large size, but the rest of the group are small and verysimilar in form and colour, so that they are difficult to diagnose,and much remains to be found out as to their distribution inCanada. Two further peculiarities of the family may be re-ferred io, the bright colouring of the males at breeding time inthe spring, and the division of the air-bladder into two or threecompartments by ti-ansverse Fig. 23.—The Red Horse. Moxostoma macrolepidotum. |.(U. S. Fish Commission.) 10. The Siluroids and Cyprinoids, like several other fomi-lies of Teleostei, have an open duct between the air-blaclderand the oesophagus; all the families which possess this areknown as the Physotomous Teleosts, while those in which theair-duct is absent are known as the Physoclystous Teleosts. Weshall find some familiar forms among the remaining Physostomi,which haA^e the anterior vertebrfe separate from each other andunconnected with the air-bladder. Foremost in importance,from an economical point of view, is the family of the Salmon-idse, which contains so many valuable food-fishes. Chief amongthese is the Atlantic salmon, (^Salmo solar, Linn.) (Fig. 24) HIGH SCHOOL ZOOLOGY. 59 which ascends rivers on both sides of the Atlantic for the pui-pose of spawning, and is consequently described as migratoryor anadromous, althongh it is able to live al
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Keywords: ., bookcentury1800, bookdecade1880, booksubjectzoology, bookyear1889
