. Chimæroid fishes and their development. Fishes; Chimaeridae. DEXTAL PLATES OF LARVAL CHIM^ROIDS. I2S as conspicuous, is none the less suggestive when we compare it with the strictly tritoral conditions shown in Harriotta, fig. 94 A. DEXTAL PLATES OE LARVAL Furthermore, if one compares the dental plates in Chimaeroids of different stages of growth, one is impressed with the evidence of larval adaptations. The plates of a Chimsroid recently hatched {C. colliei) are surprisinolv laro-e in size, but instead of spreading out in lOJ the form of crushing plates, they protrude marginal
. Chimæroid fishes and their development. Fishes; Chimaeridae. DEXTAL PLATES OF LARVAL CHIM^ROIDS. I2S as conspicuous, is none the less suggestive when we compare it with the strictly tritoral conditions shown in Harriotta, fig. 94 A. DEXTAL PLATES OE LARVAL Furthermore, if one compares the dental plates in Chimaeroids of different stages of growth, one is impressed with the evidence of larval adaptations. The plates of a Chimsroid recently hatched {C. colliei) are surprisinolv laro-e in size, but instead of spreading out in lOJ the form of crushing plates, they protrude marginally, forming relatively high edges and function evidently in cutting. Moreover, the substance of these juvenile plates is glassy {cf. Schauinsland, re vitrodentine) rather than horn-like or chalk\% and their margins are sharp and brittle. It is clear, therefore, that the plates grow during earlier stages, notably at their outer or secant margins, and it is a probable conclusion that this condition of growth is corre- lated with the special feeding requirements of the young. In later stages the plates broaden and thicken, the secant edges become less and less conspicu- ous, and graduallv the tritoral Figs, Dental plates (somewhat diagrammaric) ^ ' ot three individuals measunng respectively lU, 4V, and 64 cm. At A the areas appear. i ne latter, at lateral aspect of the vomerine and palatine plates is given. least in the species examined, are developed first vaguely, in extended tracts or ridges, and in these there later arise discrete eminences. This is the condition indicated above in Callorhynchus {cf. also with fig. 95 the juvenile plates shown in fig. 106); it is even more marked in Chimcera colliei, and it is to be observed in such a form as Harriotta. Of the last form we may introduce sketches of three stages of the dental plates.* In the first (fig. 107) the plates are frail, although well formed, and with secant prosilient edges; they have alr
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Keywords: ., bookcentury1900, bookdecade1900, booksubjectfishes, bookyear1906
