. Preliminary report on the fish and fisheries of Ontario [microform]. Fishes; Fisheries; Poissons; Pêche commerciale. 431 Th" organs of tl»e senses are visible to a certain extent from a surface inspection : thus the nostrils are two apertures on each side which lead into the front and hind ends of the olfactory sacs; round the mouth there are grouped eight sensitive feelers or " barbels " (not present in all fish) : the eyes, aTthough small, are evident enough, but the ears are ent'rely sheltered within the skull and have no communication to the outside. Finally there are cert
. Preliminary report on the fish and fisheries of Ontario [microform]. Fishes; Fisheries; Poissons; Pêche commerciale. 431 Th" organs of tl»e senses are visible to a certain extent from a surface inspection : thus the nostrils are two apertures on each side which lead into the front and hind ends of the olfactory sacs; round the mouth there are grouped eight sensitive feelers or " barbels " (not present in all fish) : the eyes, aTthough small, are evident enough, but the ears are ent'rely sheltered within the skull and have no communication to the outside. Finally there are certain small holes and slits chietty on the head and along the lateral line of the body, which open into canals scales. containing sense-organs in the skia, and generally prot3cted by bony The Catfish, except for a few scales of this sort chiefly situated below the orbit (suborbital), is destitute of the ordinary scaly covering of a fish. Its skin is soft, and slimy, there being innumerable cells in the skin constantly forming this layer of mucus on the surface. But in most fish, the skin is strengthened by bony scales, which may have minute teeth projecting through the surface as in the Sharks and Sturgeons, or a continuous coat similar to tooth-enamel, as in the bony pike, but are generally covered entirely by the soft epidermis. These scales* are usually either rounded (cycloid) or with a jagged hinder edge (ctenoid), fig. 2. Their number in longitudinal or vertical rows is often used for distinguishing. Fig. 2 —A, Cycloiii Scale from Lake Hrrri\g. B, Ctenoid Scale krom Rock Bass. 6/1. species, especially those that are perforated for the organs of the lateral line referred to above. The formula for the number of scales i; then written L. G3 (as in the Common Sucker), but if it is desirable to take into account the number of longitudinal rows above and below the lateral line, these are counted in an oblique row fron the beginning of the dorsal fin downwards to the late
Size: 2076px × 1203px
Photo credit: © Library Book Collection / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1890, booksubjectfi, booksubjectfishes
