. Chimæroid fishes and their development. Fishes; Chimaeridae. 124 FISHES AND THEIR DEVELOPMENT. 105 and arrangement; in fact, one might even go so far as to maintain that from a large series of dental plates of one species of Chimsera one might obtain variants which, separateh' considered, would be placed with other species. Moreover, from the function of these crushing plates, it is not unnatural that marked differences should appear in specimens of different ages and from different localities (/. ^'., from those individuals which have lived upon different food material). In short,
. Chimæroid fishes and their development. Fishes; Chimaeridae. 124 FISHES AND THEIR DEVELOPMENT. 105 and arrangement; in fact, one might even go so far as to maintain that from a large series of dental plates of one species of Chimsera one might obtain variants which, separateh' considered, would be placed with other species. Moreover, from the function of these crushing plates, it is not unnatural that marked differences should appear in specimens of different ages and from different localities (/. ^'., from those individuals which have lived upon different food material). In short, we incline to the belief that changes in the dental plates of Chimseroids do not predicate as wide divergences in lines of descent as one would naturally expect. From the standpoint of adaptation, furthermore, admitting the extreme value of physiological adaptation in dental plates within the limits of the present group, we obtain a suggestion why phylogenetic changes are not recapitulated favorably in their devel- opment. In a form, for example, like Callo- rhynchus, in which the basal (trabecular) por- tion of the plates has become greatly devel- oped in the adult, we naturally expect that there will be less oppor- tunity—shall we say time ?—for the tritors to recur in develop- ment in a separate and finished form. If they do appear, the\' appear regularly only in. ^ofo^=lX°§»#o 0. 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 Dean, Bashford, 1867-1928. Washington, D. C. , Carnegie Institution of Washington
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1906
