52 Halicystis and Vafama. 



EXPLANATION OF PLATE XIII. 



Fig. i. Halicystis ovalis. Natural size. 



Fig. 2. ,, Chromatophores and nuclei. Drawn by Dr. Schmitz. 



Fig. 3. ,, The same from a photograph ( x 1200). 



Fig. 4. Section of membrane with layer of contents ( x 150). 



Fig. 5. Halicystis parvula. Chromatophores and nuclei. Drawn by Dr. Schmitz. 



Fig. 6. a and <, Valonia venlricosa. Natural size. 



Fig. 7. ,, Rhizoids ( x 66). 



Fig. 8. a, b, c, d. Reproductive bodies ( x 375). 



Fig. 9. ,, ,, Chromatophores ( x 750). 



Fig. 10. ,, Section of wall, showing exfoliation ( x 150). 



