. On the anatomy of vertebrates [electronic resource] . e developementof a Mammalian tooth :but the e eruptive stagetakes place without pre-vious inclosure of the follicle and matrix in the substance of thejaw-bone. In Balistes, Scarus, Sphyrcena, the Sparoids, and many otherFishes, the formation of the teeth presents all the usual stageswhich have been observed to succeed each other in the dentitionof the higher Vertebrates : the papilla sinks into a follicle, becomessurrounded by a capsule, and is then included within a closedalveolus of the growing jaw, figs. 259, 261, c, where the develope
. On the anatomy of vertebrates [electronic resource] . e developementof a Mammalian tooth :but the e eruptive stagetakes place without pre-vious inclosure of the follicle and matrix in the substance of thejaw-bone. In Balistes, Scarus, Sphyrcena, the Sparoids, and many otherFishes, the formation of the teeth presents all the usual stageswhich have been observed to succeed each other in the dentitionof the higher Vertebrates : the papilla sinks into a follicle, becomessurrounded by a capsule, and is then included within a closedalveolus of the growing jaw, figs. 259, 261, c, where the develope-ment of the tooth takes place and is followed by the usual eruptivestages. A distinct enamel-pulp is developed from the innersurface of the capsule in Batistes, Scarus, Sargus, and Chryso-phrys. In the formidable Barracuda (Sphyi*<zna) the loss or fracture ofthe lancet-shaped teeth, in the conflict with a struggling prey, isrepaired by an uninterrupted succession of new pulps and existence of these is indicated by the foramina, which are. Vertical section of jaw and teeth (Lamna). v. TEETH OE FISHES. 383 situated immediately posterior to, or on the inner margin of, thesockets of the teeth in place: these foramina lead to alveoli ofreserve, in which the crowns of the new teeth, in different stagesof developement, are loosely embedded. It is in this position ofthe germs of the teeth that the Sphyramoid fishes, both recentand fossil, mainly differ, as to their dental characters, from the restof the Scomberoid family. It is interesting to observe that the alternate teeth are, ingeneral, contemporaneously shed: so that the maxillary armour isthus preserved in an effective state. The relative position ofthe new teeth to their predecessors, and their influence uponthem, resembles, in the Spltyrcena, some of the phenomena whichwill be described in the dentition of the Crocodilian the Crocodiles the present voracious Fish also approximates inthe alveolar lodgem
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Keywords: ., bookcentury1800, booksubject, booksubjectbirds, booksubjectfishes
