FIG. 4. Shows a portion of the cytoplasm of an epithelial cell in the intestine of 

 the mosquito (Aedes aegypti). A part of a nucleus is shown at the upper left. 

 The nuclear envelope is not unlike that found in other kinds of cells. The dominant 

 element in the cytoplasm of this cell is again the rough form of the endoplasmic 

 reticulum (rer). In its distribution and tendency to appear in clusters of lamellae, 

 it resembles that found in the vertebrate liver cell. The smooth form of the retic- 

 ulum (ser) is also represented in these cells and, as in liver cells, is closely asso- 

 ciated with masses of glycogen (gl). The Golgi (G) is represented by separate 

 stacks of laminate vesicles. Thus in a cell from a very different biological species, 

 one finds a distinctive variant of the ER, but a variant which closely resembles 

 that common to liver cells of other organisms. It will be interesting to learn 

 whether these cells share any of the functions of liver cells. (Courtesy of Thomas 

 F. Roth.) Magnification: 27,000 X. 



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