Abstract: | The flagellar apparatus of an undescribed species of Chrysochromulina Lackey that bears “eyelash” scales is reconstructed. The transitional region consists of two transitional plates each with an axosome, with no stellate pattern between them. Fine osmiophilic rings lie between the flagellar membrane and the outer doublets in the transitional region. The two jagella and the haptonema are inserted in a subapical depression that is lined ventrally by a spine-like projection formed by one of the parietal chloroplasts. The angles of insertion are similar to those of some other Chrysochromulina species in that both the haptonema and the right basal body lie at an extreme angle to the left basal body. The connectives of the apparatus consist of a striated distal band with a dorsal extension to the R1 and a ventral extension overlying the R2, a striated distal accessory band, an auxiliary connective from the right basal body to the adjacent ventral chloroplast, a well-developed intermediate band, two striated proximal bands, and a striated proximal accessory band. Of the microtubular roots in this Chrysochromulina species, three are associated with the left side of the cell (an R1 of 8+3; a small crystalline compound root, the R1C, associated with the R1; an R2 of three micro-tubules), and two are associated with the right basal body (an R3 of 2/2 microtubules with which the single-stranded R4 converges to form a 2/2+1 and then a 2/3 tiered arrangement). Comparisons are drawn with other species in the genus and related genera, particularly Prymne-sium. |