Figure 6: White and purple vesicles of Aplysia parvula. (a) Adjacent white (lumen filled with vacuoles and filamentous material) and purple (lumen of electron dense, granulate material) vesicles separated by muscle. (b) White vesicle with peripheral cytoplasmic layer surrounding a lumen filled with low electron dense, filamentous material and small vacuoles. ((c)–(e)) The cell membrane of white vesicles is infolded (arrows) into the peripheral cytoplasmic layer and these invaginations contain low electron dense, filamentous material. m, muscle; mi, mitochondrion; r, purple vesicle; v, vacuole; w, white vesicle. Scale bars: (a) and (b) = 1 μm; (c)–(e) = 100 nm.