. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 220 COMPARATIVE ANATOMY infundibulum and hypophysis extend far backwards: details regarding the pineal apparatus are not known. Reptiles.—The brain of Reptiles reaches a considerably higher stage of development than that of the forms already described, and the individual parts overlie one another to a greater extent, especially in the Agama^ and Ascalabota?. In the brain of Dipnoi and Amphibia there are comparatively few cellular elements in the outer layer of the pallium, and the larger masses of cells (central gray matt
. Comparative anatomy of vertebrates. Anatomy, Comparative; Vertebrates. 220 COMPARATIVE ANATOMY infundibulum and hypophysis extend far backwards: details regarding the pineal apparatus are not known. Reptiles.—The brain of Reptiles reaches a considerably higher stage of development than that of the forms already described, and the individual parts overlie one another to a greater extent, especially in the Agama^ and Ascalabota?. In the brain of Dipnoi and Amphibia there are comparatively few cellular elements in the outer layer of the pallium, and the larger masses of cells (central gray matter) line the ventricles: in the Reptilia a peripheral shifting takes place, giving rise to the Parict'll •>,•,„,„ -^jfl&^^^jjfo ,•„,p . Nerve Epithelial roof of •jg£f3fa<fj^ Wy .Jt3 pineal organ (epiphysis) 3rd ventricle V*«ae* \\1KI Superior commissure _ - _. FIG. lf>8.—SKKTCH UK THE PINEAL APPAKATUS OF HATTERIA. (After Dendy.) formation of a definite cortex, containing the characteristic pyra- midal cells such as are present in all the higher Vertebrates. It appears that the first differentiation of a cortex phylogenetically was connected with the olfactory sense : while in Fishes, for example, the olfactory tracts terminate in the corpora striata, most of their fibres extend into a definite region of the pallium from Reptiles onwards. Thus an " olfactory cortex " is formed, to which other centres are gradually added in the ascending series of Vertebrates. The pallial commissures (Fig. 165), like those of Amphibians, are not large relatively, but in addition to an anterior pallial or hippocampal commissure, traces are present of a so-called "fornix" (posterior pallial commissure, p. 201); the hippocampal lobes. 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 origin
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