Fig. 1 shows the Japanese sillago with green spots on its body surface
(A) and which were especially abundant along the lateral line
(B). Green spots or mucilaginous clumps were also extensive within
the palate (C). On closer observation (D), the spots were seemingly embedded
beneath the fish scale or the surface skinwhere they were apparently
entrenched intramuscularly (E). In the SEMmicrographs, each spot
was dome-shaped and totally covered by fish skin (F). Upon dissection of
the spot, a granular clusterwas seen (G) composed of numerous coccoid
cell clumps (H). Due to the frozen condition prior to appropriate fixation,
morphological preservation of the cellswas unsatisfactory as seen under
SEM, but it was seen that some cells maintained an ellipsoidal coccoid
outline showing small warts on their surfaces (I). The cell length
was 7.3 ± 0.7 μm (n = 30). From the histological sections (Fig. 2),
hematoxylin-stained algal cells were tightly packed in a dome-cavity
(asterisks in the figure) and delineated by a thickmuscularwall (arrows
in the figure) from the fish flesh. The individual algal cells were never
seen within the flesh tissue but always found within the domes.