Body muscles of the lamprey. Some structural features of the T system and sarcolemma

Electron microscopic studies confirm and extend the conclusions derived previously from a quantitative biochemical study of the phagocytosis of polystyrene and polyvinyltoluene latex beads by Acanthamoeba (1). Latex beads 1.305, 1.90, and 2.68 µ in diameter are ingested individually, with each bead tightly surrounded by a membrane derived from the plasma membrane. Latex beads 0.557, 0.264, 0.126, and 0.088 µ in diameter are accumulated at the surface of the ameba and then phagocytosed, with many beads tightly packed within one membrane-bounded vesicle.