PLATE 1 



EXPLANATION OF FIGURES 



1 Thyreoid of Emys europaea. Fixation: alcohol 96 per cent. Staining: 

 alcoholic carmine solution of the Zoological Station of Naples, Weigert's fluid 

 picric acid. 8* objective, 4 ocular. The colloid is stained yellow, the cellular 

 nuclei red, the elastic fibers blue. A portion of the external capsule has been 

 left in place. Note how numerous are the elastic fibers in the capsule and how 

 extremely scarce are they in the intervesicular connective. 



2 Same. Fixation: Fiemming's fluid. Staining: Heidenhain's haematoxy- 

 lin. 7* objective, 4 ocular. In some places the intervesicular connective has 

 given way and the alveoli appear detached . 



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