Figure 1.

Transmission electron micrographs of rocky‐shore benthic foraminifera observed in this study. Planoglabratella opercularis (a and b), Glabratella patelliformis (c), Angulodiscorbis quadrangularis (d), and Elphidium crispum (e and f). Scale bar indicates 5 μm (a, c, and e), 2 μm (b and d), or 1 μm (f). k, kleptoplast; fv, food vacuole; v, vacuole; m, mitochondria; p, peroxisome; n, nucleus; and pp, pore plug. Pararotalia nipponica (g and h), Cibicides lobatulus (i and j), and Quinqueloculina yabei (k and l). Scale bar indicates 5 μm (i and k), 2 μm (g), 1 μm (j), or 500 nm (h and l). *endobiotic algae; fv, food vacuole; v, vacuole; cp, chloroplast; cm, cell membrane of the endobiotic algae; cy, cytoplasm of the endobiotic algae; pp, pore plug; and cl, clay mineral