Nomarski interference microscopy of Volvox reticuliferus Nozaki sp. nov.

(A) Surface view of asexual spheroids showing small somatic cells and larger reproductive cells (gonidia). (B, C) Somatic cells in the anterior portion of asexual spheroid showing lack of cytoplasmic bridges between cells. (B) Surface view showing stigma. (C) Optical section showing pyrenoid. (D, E) Asexual spheroid stained with dilute aniline blue, showing a broad secondary boundary layer (asterisk) of the gelatinous matrix surrounding each somatic cell. (D) Front view of somatic cells. (E) Side view of somatic cells. (F) Surface view of chloroplast of gonidium of asexual spheroid. Note presence of radial striations in the chloroplast surface. (G) Pre-inversion stage. Note morphological differentiation of gonidia of the next generation. (H, I) Mature male spheroids with sperm packets. (J) Female spheroid with eggs. (K, L) Two views of mature zygotes with a reticulate wall. Abbreviations: e, egg; g, gonidium; p, pyrenoid; s, stigma; sp, sperm packet. (A-C, H, I) Strain VO123-F1-7. (D-G) Strain VO123-F1-6. (D-G) Strain 2013-0703-VO2. (K, L) Strains 2013-0703-VO2x3.