Claus et al.: "Organized Elements" in Chondrites 595 



of organized elements is not a true fluorescence. They suggested that bire- 

 fringent particles may appear red when viewed with ultraviolet light in the 

 fluorescent microscope. The reason for this could be that the usual filters 

 transmit a portion of the red part of the spectrum. However, the particles 

 which were described previously were not birefringent when examined in a 

 polarizing microscope and they were photographed with an additional set of 

 filters (Corming 7-59 + Wratten 2B + Zeiss 064 + 061) that permitted mainly 

 blue light to enter the microscope. Consequently, the argument of Fitch and 

 Anders is not valid in this case. 



The microscopical assembly used for the fluorescence studies enabled one to 

 view objects in UV darkfield illumination, as weU as in regular transmitted 

 light. In this way it was possible to select organized elements of distinct 

 morphologies for the fluorescence studies. It is true that a few irregularly 

 shaped particles also fluoresced in greenish-yellow light. These particles 

 could be easily fragments of organized elements, broken during the crushing 

 of the meteorite samples. On the other hand, the majority of the irregularly 

 shaped particles fluoresced with a different color than the organized elements; 

 they emitted bluish-white light and they were probably mineral particles (or 

 particles coated with bituminous matter). 



Fluorescent microscopy is also useful to demonstrate certain morphological 

 features which are not readily visible in transmitted light. Mitochondriatic 

 granules become visible in the UV microscope when they emit fluorescent light 

 with or without fluorochromation (Drawert and Metzner, 1956). Similarly, 

 fluorescent microscopy was found to be useful to visualize certain morphological 

 features that were not visible when the organized elements were examined in 

 regular, transmitted fight or with phase contrast microscopy. Figure 106 

 shows an organized element that fluoresced with greenish-yeUow light. 

 Centripetal ribs were found to be present around the walls. This morphological 

 feature is rather unusual, because only a few Diatom species are known to show 

 centripetal ribs (Hustedt, 1930). This feature is not identical with the internal 

 septae of Coccolilhoplwrideae, Silicoflagellatae, Foramiiiiferae, and certain Di- 

 atoms such as Naviculaceae etc., the septae of which extend much farther into 

 the cell. The general habit, as seen in transmitted fight, figure 10a, resembles 

 a Trachelomonas, a genus of aquatic protophyta, except of the location of the 

 pore. However, a Trachelomonas does not have centripetal ribs. The presence 

 of the centripetal ribs are of particular interest regarding the argument of 

 Fitch and Anders about pollen grains. The exo-exine of pollen grains show 

 centrifugal thickenings but they never show centripetal ribs. Fames and 

 MacDaniels (1947) state on p. 49 in their "Introduction to Plant Anatomy" 

 that: "The external wall layers and surface projections of spores and pollen 

 grains are formed in part by tapetal fluid or mother cell cytoplasm." (There- 

 fore, only centrifugal thickenings can occur on walls of pollen grains.) It 

 seems unlikely, that the particles shown in figure 10, a and 6, are pollen grains 

 or spores. It is known that spores of fungi do not fluoresce. Hofler and 

 Pecksieder write (1942, p. 117): "Angesichts der weiten Verbreitung primar 

 Fluoreszenz im Gewebe der Pilzkorper beriihrte uns die Beobachtung urn so 

 auffalliger, dass die Sporen der Hulpilze im UV-Lichl nicht fluoreszierten, viel- 

 mehr meisl vdllig unsichtbar waren." 



