22 S. SAGUCHI 



phile apparatus exists in the shape of dehcate tortuous filaments 

 (fig. 25). The Golgi apparatus consists of spherical or elliptical 

 corpuscles of irregular contour (figs. 34 to 36). Pigment gran- 

 ules are not seen. The cell-body of this type is cylindrical or 

 conical in shape; its spherical nucleus is situated near the basis of 

 the cell; it is surrounded by a thick nuclear membrane which is 

 often thrown into folds and stains deeply with iron-hematoxyhn; 

 the nuclear net is very distinct. The nucleolus is always 

 smaller than that of the acinus cell. 



2. b cells. The specific granules of b cells are faintly stained 

 so that the granulation of the cytoplasm is indistinct (figs. 1 to 

 4, b, 16, 17). As is the case with a cells, mitochondrial filaments 

 cannot be found. Lipoid corpuscles, however, are always pres- 

 ent in b cells, though most of them are small in size (figs. 2 b, 

 16). The urano-argentophile apparatus is fairly well developed, 

 and is either filamentous or granular in form (figs. 26 to 28). 

 The Golgi apparatus occurs in the form of the typical network 

 which may be regarded as being at the height of its development 

 (figs. 38, 39, 40, 42). The 6-cell is cubical or cylindrical in form 

 and contains an elliptical nucleus, the boundary of which, though 

 indistinct, has generally an even contour; it is in the middle of 

 the cell-body. The nuclear net stains very faintly. The nu- 

 cleolus is small. 



3. The c cells are the most ill- defined type of islet cells. The 

 granulation of the cell-body is very indistinct and is replaced 

 here and there, especially near one end of the cell, by a homo- 

 geneous protoplasm (figs. 52, 53). Although it is certain that 

 these cells contain neither mitochondria nor lipoid corpuscles, 

 it is difficult to decide in what form urano-argentophile and ar- 

 gentophile granules, as well as the intracellular apparatus of 

 Golgi occur. It seems, however, that these structures are never 

 found in a well-developed state (figs. 31, 32). The c cells are 

 generally small in size and either cubical or narrow, long and 

 cylindrical in shape. The nucleus is irregularly shaped and sur- 

 rounded by a wrinkled boundary membrane; one or more small 

 nucleoli, which are suspended in the ill-defined nuclear net, are 

 visible in the nucleus. 



