C^2 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 56 



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PLATE 7 



Fig. 20. The union of II aa and Illba in the flexible zone. (Magnified 350 



diameters. Photographed with Zeiss achromat E, Ocular 2.) 



Fig. 21. The union of Ilaa and Illba in the flexible zone. (Magnified 200 I 



diameters. Photographed with Zeiss achromat E, Ocular 2.) 



Fig. 22. The union of Ilaa and Illba in the flexible zone. (Magnified 100 



diameters. Photographed with Zeiss apochromat 16, Ocular 6.) 



i 



I 



