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| Keywords: The Quarterly journal of the Geological Society of London (14076831084).jpg 54 <br> PEOr E W CLATPOLE ON PTEPvASPIDIAN FISH IX <br> above them in the upper division of the vascular layer and below <br> the minute channels of the upper and outer surface with which <br> they are apparently continuous These highest canals to which <br> possibly the term furrows would be more applicable have no <br> branches or outlets so far as I have been able to determine except <br> the passages just mentioned nearly as wide as themselves whereby <br> communication is effected with the vessels lying below them and <br> already described Both may be readily seen sectionaUy and longi- <br> tudinally by cutting thin slices of the shield in the proper direction <br> see figs 2 3 4 <br> – Sections of the Shield of Palseaspis <br> Kg 2 <br> I ig 3 <br> Fig 2 Vertical longitudinal section showing a basal layer ; b cellular layer ; <br> c vascular layer lower portion upper or tubular portion <br> Fig 3 Vertical transverse section showing a basal layer ; 6 cellular layer ; <br> c vascular layer Q- lower upper portion <br> Fig 4 Horizontal section through vascular layer of shield showing the lower <br> branching vessels the upper vessels or channels and the tubules seen <br> from below <br> Lastly there yet remains to be described the most remarkable <br> part of this outer or upper vascular layer To this I have given <br> the name of the tubular division From the larger and lower of the <br> two sets of vessels just described and from its upper side there issue <br> a vast number of minute tubules which branch and run to right and <br> left and upward from the parent vessel forming a minute and beau- <br> tiful forest-like growth Pilled as they are with opaque matter <br> they stand out distinctly like dendrites on marble on the light yel- <br> low surface of the material of the vascular layer They do not form <br> any connexion with the large channels or furrows lying to right 37046892 114009 51125 Page 54 Text 41 http //www biodiversitylibrary org/page/37046892 1885 Geological Society of London Biodiversity Heritage Library The Quarterly journal of the Geological Society of London v 41 1885 Geology Periodicals Smithsonian Libraries bhl page 37046892 dc identifier http //biodiversitylibrary org/page/37046892 smithsonian libraries Information field Flickr posted date ISOdate 2014-04-30 Check categories 2015 August 26 CC-BY-2 0 BioDivLibrary https //flickr com/photos/61021753 N02/14076831084 2015-08-26 04 53 00 cc-by-2 0 PD-old-70-1923 The Quarterly journal of the Geological Society of London 1885 Photos uploaded from Flickr by Fæ using a script | ||||
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