EXPLANATION OF FIGURES. 



The figures on Plates 3, 4, and figure 16 are photographs of preparations. All the other figures were drawn with the 

 camera lucida at stage level with Zeiss apochromat 2 mm., oil-immersion objective. The compensatory ocular 8 was 

 used for figures 1, 2, and 3, ocular 6 for all others. 



ABBREVIATIONS IN ALL FIGURES THE SAME: 



C, capillary Grbl., granuloblast 



Endc, endothelial cell Grc, granulocyte 



Erbl., erythroblast Hbl., hemoblast 



Ere, erythrocyte Msc, mesenchymal cell 



Plate 1. 



Fig. 1. Small muscular area in the wing of an embryo 9 days old, 2 days after grafting adult splenic tissue on its 

 ailantois. Mfn. Muscular fiber nuclei. VVc. Wandering cells. 



Fig. 2. Cleft between muscle bundles in a tangential aspect. Wandering cells in great numbers, some of them as 

 basophilic hemoblasts, others more approaching the structure of histiotopic wandering cells, some of the wandering cells 

 forming plasmodial masses. 



Fig. 3. Granuloblasts differentiation of the mesenchymal strands between muscular fibers, five days after grafting. 



Fig. 4. Part of the testis. The greater part of the mesenchyme between the testis cords is transformed into amoeboid 

 cells, hemoblasts, and granuloblasts. Tc, testis cord, Gc, germ cells. 



Plate 2. 



Fig. .5. Part of ovarian tissue in proximity with the germinal epithelium. Granuloblastic transformation of the 

 mesenchyme in the ovary eight days after grafting. 



Fig. 6. Part of adrenal tissue. Adr. e., adrenal epithelium. Phc, phaochrom cells. X, phaeochromoblasts. 

 Fig. 7. Area of fat-tissue with numerous granuloblasts between the fat^cells. 



Plate 3. 



Fig. 8. Area of muscular tissue in leg. Heavy strands on hemoblastic tissue separate the groups of muscular fibers. 



Fig. 9. Same as figure 3. 



Fig. 10. A vessel in the liver. Its wall is heavily infiltrated with hemoblasts and granuloblasts. 



Fig. 11. Area of granuloblastic tissue around a large vessel. 



Plate 4. 



Figs. 12. and 13. Parts of ovarian tissue with an extensive granuloblastic transformation of its mesenchyme. 

 Fig. 14. Myeloid metaplasia of the mesonephros. Glomerule and convolute tubules wrapped into a dense granu- 

 loblastic tissue. 



Fig. 15. Anlage of a feather. A great part of the mesenchyme in its axis transformed into granuloblastic tissue. 



Plate 5. 



Fig. 16. A papilla of the pharyngeal mucosa. A great part of its stroma is transformed into granuloblastic tissue. 



Fig. 17. Capillary net in the connective tissue septa between the muscle bundles in the leg, 8 days after grafting. 

 The capillaries are distended by hemoblasts and young stages of erythroblasts, the mesenchyme between them trans- 

 formed into granuloblastic tissue. 



Fig. 18. Longitudinal section of small nerve (n) and vessel. In the perineurium and in the mesenchyme around 

 the vessel numerous free cells are detached from the mesenchymal syncytium. These develop into hemoblasts and 

 granuloblasts. 



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