THE ORIGIN AND DEVELOPMENT OF GASTRIC GLANDS. 



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FIG. 18. Cross-section through the cardiac region of larval Ainhlystoma of II 

 mm. total length. Gilson's, modified, a., " ovoid cell,'' or gland anlage, in process 

 of division; b.m., basement membrane; d. , depression at the surface to form the 

 future excretory duct; <?/., epithelium of the surface; m., mesodermic tissue forming 

 the muscular layers; y., yolk spherules which obscure the cell outlines. Obj. 7, 

 Oc. 2. 



