. Catalogue of the fishes in the ... Museum. . <S. salar. S. bracki/poma. In young specimens of all Salmonoids the prceoperculum has a very short lower limb ; but whilst in some species it lengthens with age, its development in a horizontal direction is arrested in otlicrs. 2. The widtJi and strength of the maxUlarij of the adult fish. To show this character in two distinct species, we have given woodcuts of the maxillaries of females (12 inches long) of S. fario and S. leve- nensis of the same size. S. fario. S. levenensis. In yoimg specimens of all Salmonoids the maxillary is compara- tiv
. Catalogue of the fishes in the ... Museum. . <S. salar. S. bracki/poma. In young specimens of all Salmonoids the prceoperculum has a very short lower limb ; but whilst in some species it lengthens with age, its development in a horizontal direction is arrested in otlicrs. 2. The widtJi and strength of the maxUlarij of the adult fish. To show this character in two distinct species, we have given woodcuts of the maxillaries of females (12 inches long) of S. fario and S. leve- nensis of the same size. S. fario. S. levenensis. In yoimg specimens of all Salmonoids the maxillary is compara- tively shorter and broader, somewhat resembling that of a Coregorms; yet this bone offers a valuable character for the determination of the young of some species; for instance, in a yoimg *S'. cambricus it ex- tends scarcely to below the centre of the eye, whilst in a S. fario of the same size it reaches to, or even beyond this point. 3, The size of the teeth, those of the intermaanllarits excepted. 4. The arrangement and the permanence or deciduousness of the vomerine teeth. In some species the vomer is normally armed with a double or single series throughout life, although of course some of the teeth are frequently accidentally lost; in others these teeth dis- appear gradually with age, the hinder ones first, so that finally the anterior only remain. In order to ascertain the arrangement of the teeth, it is necessary to remove the gingiva. Frequently the teeth stand in a distinctly double or single series, or they are placed alter- nately ; but frequent irregularities occur which render this character vague, or even unsafe, so that some zoologists have rejected it entirely as unreliable. However, when a greater number of individuals, really belonging to the same species, are examined, a pretty safe conclusion may be arrived at as regards the arrangement of these Please note that these images are extracted from scanned page images that may have been digitally enhanced for
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