A treatise on zoology . - form one rigid arch. How far thesethree pterygoid bones are all present in primitive and earlj formsis uncertain. The palato-pterygoid arch articulates in front with the ethmoidcartilage laterally, by an ethmo-palatine articulation. The rightand left arches do not, therefore, meet below the snout as inthe Chondrichthyes (except in the Acipenseroidei). It is interest-ing to notice that in certain (perhaps in all the primitive forms) ofthe lower Teleostomes (Pycnodontidae, Aspidorhynchidae, Macro-seraiidae, Pholidophoridae, Lepidosteidae, Lepidotidae, Amiidae) themetapt
A treatise on zoology . - form one rigid arch. How far thesethree pterygoid bones are all present in primitive and earlj formsis uncertain. The palato-pterygoid arch articulates in front with the ethmoidcartilage laterally, by an ethmo-palatine articulation. The rightand left arches do not, therefore, meet below the snout as inthe Chondrichthyes (except in the Acipenseroidei). It is interest-ing to notice that in certain (perhaps in all the primitive forms) ofthe lower Teleostomes (Pycnodontidae, Aspidorhynchidae, Macro-seraiidae, Pholidophoridae, Lepidosteidae, Lepidotidae, Amiidae) themetapterygoid sends inwards a process (Fig 239), which quite or. asp a. ap Fig. :i40. Iniiei- view of the lower jaw of .-Ivuia colva, L. (After Allis.) «, articular ; an, angular ;or, dermarticular ; , anterior splenials ; cp, coronoid cartilaKe ; d, dentary ; sa, supra-angular ; s,in,, niento-Meckelian ; sp, splenial with minute teeth ; t, marginal tooth. nearly articulates with the trabecular region of the skull betweenthe optic and the trigeminal foramina (van Wijhe [4!)-lr], Reis [349]);a vestige of this process appears in the embryos of some Teleostei{Salmo, Swinnerton [431], Winslow). This connection mayperhaps represent the lower articulation of the quadrate in auto-sty lie skulls—the pedicle of the suspensorium (p. 97). In thatcase it would point to the Teleostomi having preserved a traceof the original connection between the mandibular arch and thecranium (p. 97). The large cartilaginous hyomandibular generally ossifies in twopieces—a hyomandibular bone above articulating with the skull,and a symplectic below, connected Avith the
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Keywords: ., bookcentury1900, bookdecade1900, bookpublishe, booksubjectzoology
