Electron Microscope Observations on the Myoblast of the Regenerating Forelimb of the Adult Newt.

Young myoblasts of regenerating limb blastemata of adult newts at 60 days after amputation contained many glycogen particles and vacuolar sarcoplasmic reticula scattered in the cytoplasm. In more differentiated myoblast containing numerous myofilaments, glycogen particles were seen in the sarcoplasm, but in a much smaller amount than in young ones. Sarcoplasmic reticula in somewhat tubular form were also observed among myofilaments. As differentiation of the myoblast proceeds, vacuolar sarcoplasmic reticula became to be located on the level of the Z band of the myofilament