. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. EDINGEB: PARIETAL FORAMEN parietal eye. This quite distinctive feature last occurred, in Pisces, in the Carboniferous period; iu Amphibia, in the Triassic. Among the extant vertebrates with an ossified cranial roof, the genuine parietal foramen is found only in the tuatara and in lizards, that is, only in animals that have a photoreceptive para- pineal organ. If one doubts that this association existed also in extinct vertebrates, one may as well doubt that the orbits of fossil skulls contained Fig. 2. A, Parie
. Bulletin of the Museum of Comparative Zoology at Harvard College. Zoology. EDINGEB: PARIETAL FORAMEN parietal eye. This quite distinctive feature last occurred, in Pisces, in the Carboniferous period; iu Amphibia, in the Triassic. Among the extant vertebrates with an ossified cranial roof, the genuine parietal foramen is found only in the tuatara and in lizards, that is, only in animals that have a photoreceptive para- pineal organ. If one doubts that this association existed also in extinct vertebrates, one may as well doubt that the orbits of fossil skulls contained Fig. 2. A, Pariecal eye filling parietal foramen (Anolis sp., after Spencer; enlargement not known). B, Parietal eye in exceptionally wide foramen {Agama sanguinolenta, after Schmidt; x 30). Functions other than visual have been attributed to the parie- tal organ of lizards for almost a century. It has also been regarded as an inactive rudiment of a larger organ which, in Reptilia of the Past, had an unknown, presumably sensory func- tion, related to conditions not occurring in the Present. The majority of students, however, have realized that its structure clearly points to one function: photosensitivity. Thermosensitiv- ity may be associated with this, and granules apparently secre- tory in nature have been found in the organ; but, mainly, the. 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 Harvard University. Museum of Comparative Zoology. Cambridge, Mass. : The Museum
Size: 1318px × 1896px
Photo credit: © Book Worm / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookauthorharvarduniversity, bookcentury1900, booksubjectzoology
