. A descriptive catalogue of the marine reptiles of the Oxford clay. Based on the Leeds Collection in the British Museum (Natural History), London ... Reptiles, Fossil. OPHTHALMOSAUEUS. the anterior wall of which is formed by the upper surface of two prominent bosses, separated by a deep notch and each terminating in a surface for cartilage : these are the processes called by Siebenrock *, in his account of the skull of Hatteria, the lower cylindiical processes [) ; they mark the beginning of the presphenoidal region of the basis cranii, which remained unossified. Beneath them is the post
. A descriptive catalogue of the marine reptiles of the Oxford clay. Based on the Leeds Collection in the British Museum (Natural History), London ... Reptiles, Fossil. OPHTHALMOSAUEUS. the anterior wall of which is formed by the upper surface of two prominent bosses, separated by a deep notch and each terminating in a surface for cartilage : these are the processes called by Siebenrock *, in his account of the skull of Hatteria, the lower cylindiical processes [) ; they mark the beginning of the presphenoidal region of the basis cranii, which remained unossified. Beneath them is the posterior end of the parasphenoid (pas.), which is adherent to the ventral face of tliis bone, as described below. The hollow bounded by the upper surface of the lower cylindrical processes below, and by the posterior clinoid process behind, is the pituitary fossa {), into which, as already noted, the very wide carotid canal opens and passes downwards Text-fiff. fias. ^5^ Basisphenoid of OpJitJialmosawus: A, from below ; B, from the front. (R. 2162, | iiat. size.) , foramen for a branch of the carotid artery; , internal carotid foramen; jjfw., parasphenoid; , posterior clinoid processes ; , pituitary fossa ; p^/., facet for pterj-goid ; }., pterygoid processes ; , lower cylindrical processes of basisphenoid. and backwards, its single ventral aperture being situated about the middle of the ventral face of the bone : this lower opening is usually more or less asymmetrical in form. In some of the Liassic Ichthyosaurs, as pointed out by Cuvier f and more fully by Maggi;];, tliere are two posterior openings, separated, in some cases at least, by the posterior end of the parasphenoid (see text-fig. 6, C) ; this condition seems to be the most primitive, since in Ilaiteria the paired openings are situated on either side of the posterior end of the parasphenoid. In Ophtlialmosaurus the condition of the posterior end of the parasphenoid (s
Size: 2496px × 1001px
Photo credit: © Central Historic Books / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1900, bookdecade1910, booksubjectreptile, bookyear1910
