Image from page 63 of "The morphology and evolutional significance of the pineal body : being part I of a contribution to the study of the epiphysis cerebri with an interpretation of the morphological, physiological and clinical evidence" (1919)
Title: The morphology and evolutional significance of the pineal body : being part I of a contribution to the study of the epiphysis cerebri with an interpretation of the morphological, physiological and clinical evidence
Subjects: Pineal gland
Contributing Library: MBLWHOI Library
Digitizing Sponsor: MBLWHOI Library
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mity without form-ing an optic vesicle. The epiphysis is also derived from anevagination of the interbrain roof. It does not represent theoptic pedicle of the parietal eye. It is an organ sui generiswhose function is still unknown. It reveals no marked sensorycharacteristics even in selachians where it is markedly devel-oped. It appears in the entire series of vertebrates and is anancestral organ. The paired eye and epiphysis appertain to theinterbrain while the paraphysis is part of the endbrain. This 60 FUKDKKK K TILXKi AND LUTHEB F. WARRKX paraphysis shows no features of sensory function. Of thesethree encephalic divert icula from the roof-plate in Saurians,the parietal eye alone seems to have had ancestral sensoryfunction (fig. 26). In a later communication, combating the contention of Klinck-owstroem207 to the effect that the evolutional process observedin An<iuis is normal and more primitive while that in Lacertais a simple modification of this primitive form, Beraneck25 pro-
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Fig _.> Ilic epiphyseal complex in a 27 nun. embryo of Annuls fragilis, ac-cording to Beranerk, 1X92. //., paraphysis; I., velum transversum; D.s., dorsal sac; Ch., commissura ha-liennlaris; \/>ur.. ncrvus parapinealis; Id., ])arapiiHal organ; H/>., pineal organ;Sch., pars intercalaria posterior; (/>., conin.issura. posterior. posed this (juestion, If in Anguis the parietal eye is only adifferentiation of the distal extremity of the epiphysis, how inLa«r,(t does this visual organ develop parallel to the epiphysisand not dependent upon it? Beraneck maintains thai Klinc-kowstroem escapes the difficulty proposed by this question inclaiming thai the pineal eye of lynuim and f.<iccrl<i upon theone hand and Ainjnis upon the other take origin from differentparts of the epiphyseal evaginal ion. B-.raneek formulates thehypothesis that the parietal eye and epiphysis represent in THE PINEAL BODY 61 Lacerta two distinct evaginations of the thalamencephalic roof.If they appear t
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