. The Bashford Dean memorial volume :. Fishes; Sharks; Fishes, Fossil. Test-figure 21. Test-figure 22. Sections through the skull of the frilled shark, Chlamydoselachus anguineus. Text-figure 21. A transection of the basis cranii near the vertebral articulation, to show the fig- ure made by the calcareous sheath (and its processes) of the notochord, resembling a vertebra of the trunk region. cent., vertebral centnim (sheath rf notochord); di., chc^da dorsalis; cranxsv., cxanial cavity; ct., cartilage of the basis cranii; ;., neural {gorrs^; , transverse process. After Ayers, 1889,
. The Bashford Dean memorial volume :. Fishes; Sharks; Fishes, Fossil. Test-figure 21. Test-figure 22. Sections through the skull of the frilled shark, Chlamydoselachus anguineus. Text-figure 21. A transection of the basis cranii near the vertebral articulation, to show the fig- ure made by the calcareous sheath (and its processes) of the notochord, resembling a vertebra of the trunk region. cent., vertebral centnim (sheath rf notochord); di., chc^da dorsalis; cranxsv., cxanial cavity; ct., cartilage of the basis cranii; ;., neural {gorrs^; , transverse process. After Ayers, 1889, Fig. 8. Text-figure 22. Left half of the hemisected cranium, to show the relations of the notochord and cranial aorta to the basis cranii and to the pituitary prominence and space. c, cranial aorta; du, chorda doialis (notochcxd); ir., iotemal carotid artery; \., cephalic aorta; , pituitary plexus; pt., pituitary space; , transverse canal; III, third pair of aortic arches. After Avers, 1889, Fig. 3. the persistence of the notochord (ch) and the rudimentary vertebral column in the basis cranii of his specimen; but in view of the doubts that have been expressed concerning the accuracy of many of Ayers' obser\7ations on Chlamydoselachus, one should accept this description and the accompanying figures with some reserve. In Hexa-iichus the notochord Text-figure 23, nc) persists in the posterior portion of the basis cranii, much as in 'nydoselachus. My Figure 4, plate II, a medial view of the cranium of Chlamydoselachus, should be compared with Text-figure 23, shouTing a similar view of the cranium of Hexan- chus. The t^-o figures are of interest chiefly because they show the foramina for the exit of the cranial and occipital nerve Please note that these images are extracted from scanned page images that may have been digitally enhanced for readability - coloration and appearance of these illustrations may not perfectly resemble the original Dea
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