I 



PROF. EHRENEEUG ON FOSSIL INFUSORIA. 413 



Explanation of the Figures {Plate V). 



Fig. 1. Navicula (Surirella) firidis, ^ lin. magnitude, in the Kiesel- 

 guhr of Franzensbad : a, seen from tlie side surface, where 

 the mouths of the three apertures are apparent ; b, the same 

 individual from the dorsal or ventral side, in which are seen 

 all the six apertures. The stripes are internal raised bands, 

 between which were situated the ovaries of the living ani- 

 mal. 



Fig. 2. Navicula (Surirella) granulata, from the peat-bog of Franz- 

 ensbad ; a, side view ; h, the under surface. 



Fig. 3. 1. Synedra capitata, the chief form of the Kieselguhr of San 

 Fiore ; a, side surface; b, ventral surface. 2. Navicula ina- 

 qualis, side view. 



Fig. 4'. Bacillaria vulgaris ? chief form of the Kieselguhr of the Isle 

 of France. 



Fig. 5. Gaillonella distans, ^ to j^^ lin. thick : chief form of the 

 Polirschiefer of Bilin (the leaf-tripoli) ; a, b, c, seen from the 

 side; d,e, cross surfaces;/, apertures. 



Fig. 6. Gaillonella ferruginea, j^'-qq lin. thick ; the animalcule of the 

 iron-ochre ; a, with the same magnifying power ; b, two thou- 

 sand times magnified. Lyngbye has regarded this animal- 

 cule as the base of his Oscillatoria ochracea. OscillatoriEe 

 are sometimes found parasitically within it ; they belong 

 however to many different genera, and Agardh has there- 

 fore rightly regarded them as not distinct species. 

 AU the other figures are magnified 290 or nearly 300 times. 



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