5§ OYSTERS AND DISEASE. 



PLATE III.— continued. 



Fig. 13.— Section showing stomach wall, liver duct, and ca;ca (Swift, obj. \ inch). 

 Fig. 14.— Epithelium of stomach wall (Zeiss, obj. A). 

 Fig. 15.— Epithelium of a larger liver duct (Zeiss, obj. ■ 1 \). 



Fig. 16. — Epithelium of one of the smallest branches of the liver duct (Zeiss, obj. J*). 

 Fig. 17- — Section of stomach wall of a green oyster, showing green pyriform macroblasts (Zeiss, obj. A). 

 Fig. 18. — Section to show the migration of leucocytes through the stomach wall (Leitz, obj. 7). 

 Fig. 19. — Section of stomach of green Dutch oyster, to show large eosinophilous granular cells (eos), 

 and also green granular leucocytes {g.l.) migrating through the stomach wall (Leitz, obj. 7). 



PLATE IV. 



ILLUSTRATING GREEN OYSTERS. 

 Fig. 1. — " Huitre de Marennes," with the right valve removed, and the mantle lobe partly reflected, 



to show the dark blue-green colour of the gills, natural size. 

 Fig. 2. — A small part of the gill enlarged with a lens, to show the vertical gill filaments arranged in 



three crests and two troughs. 

 Fig. 3. — A series of adjacent filaments examined alive to show the arrangement of the large macroblasts, 



and also some amceboid cells on the surface (Leitz, obj. 7). 

 Fig. 4. — The macroblasts in situ, more highly magnified, from filaments fixed in formaline, and teased 



(Zeiss, ,'j oil im.). 

 Fig. 5. — Epithelium of the intestinal wall of Marennes oyster, to show the pyriform green granular 



cells (Zeiss, A oil im.). 

 Fig. 6. — Large Dutch oyster, showing the pale green gills. 

 Fig. 7. — External surface of mantle of an oyster from Nieuport, to show large granular eosinophilous 



cells, and also green granules in the epithelium (Zeiss, obj. •&). 

 Fig. S. — Another section of same to show large green granules under the epidermis (Zeiss, obj. y 5 ). 

 Fig. 9. — " Native " from the Roach River, to show the pale green gills. 

 Fig. 10. — Section of intestine of green Nieuport oyster, unstained and examined fresh to show colour 



of epithelium and liver tubules (Swift, 1 inch). 

 Fig. 11. — American oyster, living in sea-water after removal of left valve, to show corrugation of 



mantle lobe, and spotting of mantle and adductor muscle with masses of green leucocytes. 



PLATE V. 

 ILLUSTRATING THE HISTOLOGY. 



Fig. 1. — Section of edge of the mantle of Fleetwood American oyster, in which there is the green 



leucocytosis ; showing vacuolated and disorganised epithelium through which the large granular 



leucocytes have been migrating (Zeiss, v-r oil im.). 

 Fig. 2. — Section showing external surface of mantle in Marennes oyster, showing large eosinophilous 



cells (Zeiss, apochr. 1.5 mm.). 

 Fig. 3. — Transverse section of part of gill filament in Marennes oyster, showing eosinophilous cells 



(Zeiss, apochr. 1.5 mm.). 

 Fig. 4. — Eosinophilous cells in the epithelium and in the sub-epithelial connective tissue of Nieuport 



oyster (Zeiss, apochr. 1.5 mm.). 



