TAXONOMIC STUDIES ON THE CHLORARACHNIOPHYTA .1. CHLORARACHNION-GLOBOSUM SP-NOV

A third species of chlorarachniophyte, Chlorarachnion globosum sp. nov., was discovered in enrichment cultures from Guam. During most of the life cycle this species is coccoid with a distinct wall. Amoeboid cells are absent. A very thin extension of the periplastidial compartment divides the pyrenoid matrix into two longitudinal halves and the nucleomorph is located at the base of the pyrenoid. These features distinguish Ch. globosum from Chlorarachnion reptans Geitler. The two organisms share the following features: (1) each cell has several chloroplasts containing chlorophyll a and b; (2) each chloroplast is surrounded by two pairs of membranes; (3) a distinct projecting pyrenoid is present; (4) the zoospore has a single flagellum coiling around the cell body.