. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. The Skeleton S67 fishes there are two of these condyles, one on either side of the point where the notochord enters the skull, while in bony fishes the entire basioccipital region, concave on its posterior end, projects posteriorly to articulate with the centrum of the first vertebra in a joint similar to that between any two amphicoelous vertebrae. Present in all tetrapods, these condyles may occur on the basioccipital, on the two exoccipitals, or on all
. Biology of the vertebrates : a comparative study of man and his animal allies. Vertebrates; Vertebrates -- Anatomy; Anatomy, Comparative. The Skeleton S67 fishes there are two of these condyles, one on either side of the point where the notochord enters the skull, while in bony fishes the entire basioccipital region, concave on its posterior end, projects posteriorly to articulate with the centrum of the first vertebra in a joint similar to that between any two amphicoelous vertebrae. Present in all tetrapods, these condyles may occur on the basioccipital, on the two exoccipitals, or on all three of these bones, . Parietal ~J^5^'-'' Supraoccipital L^N^-' Squamosal V lyfCV.—- Foramen Magnum . N„-Opisthotic \^^;||-V- Occipital Condyle. f^irr-Middle Ear Cavity "' IP^"^/ Exoccipital sP^o"^ Basioccipital |\y'("Jjl f ~~Basisphenoid ""Quadrate Fig. 481. Posterior view of a turtle's skull. (After Reynolds.) but not on the supraoccipital. A tripartite condyle, formed by contributions from the basioccipital and exoccipitals, is found in some stegocephalians, the cotylosaurs, and most therapsids, as well as the turtles (Fig. 481), lizards, and snakes among modern reptiles. From this primitive condition there seem to have been three lines of evolution. The modern amphibians, having lost the basioccipitals, have two separate condyles, on the exoccipital bones. Some extinct reptilian groups, as well as the present-day crocodiles and also the birds, 'have a single occipital condyle on the basioccipital only, the exoc- rSXT?^ T-&g^=^|£&gj|jr-— Supraoccipital / JU-9|fer^^-- Exoccipital ^Quadratojugal !^l^^->^lgt§^^- Foramen Magnum -^-Quadrate -Transpalatine Occipital Condyle dlSTCif Basioccipital K ^ Basisphenoid j—— Pterygoid Fig. 482. Posterior view of an alligator's Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and
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Keywords: ., bookcentury1900, booksubjectanatomycomparative, booksubjectverte
