Under the light microscope, large and small types of spinal ganglion cells can be seen in the mouse. Among those of the small type bipolar cells are observed. By electron microscopy, the cells of the large type have a low electron density and those of the small type a high electron density. Bipolar cells continue to be observed among the latter. The cells of the spinal ganglia contain different cellular apparatus in enormous quantity. There are four kinds of lysosomes in the GERL, i.e. the coated vesicles, dense bodies, multivesicular bodies and autophagic vacuoles.