Cryoultramicroscopy of lower vertebrate retina.

Cryoultramicroscopy was carried out in the retina of lower vertebrates. Myeloid bodies of the pigment epithelium of turtles and synaptic vesicles and ribbons of frogs were stained negatively. Numerous altered, shaped, dense bodies, containing granular and myelinlike matrices, were found in the retinal pigment epithelium of turtle, and were thought to be lysosome. The advantages and disadvantages of this method are discussed.