movement of these organisms appears to result from a single, vigorous, co-ordinated beat by these cirri. A study of whole mounts and sections (see Figs. 2–5) largely confirms Powers' descriptions of the morphology of C. meunieri. The dimensions of fixed local material are slightly greater than for Powers' specimens: the length lies between 21 and 51μ, the width between 19 and 46μ, while the cilia are from 8 to 11μ and the cirri from 12 to 15μ long. The shorter length of cilia and cirri of fixed material is due to these structures assuming a close zig-zag pattern at death. In the Wellington material the structure of the ciliary zone is reasonably in accord with Powers' findings, though there are some differences. There is no increase in the size of the basal granules (see Fig. 2) towards the narrower (anterior) portion of the body as Powers describes. Usually 10 granules occur to a row, although counts as low as 6 were recorded. From 43 to 106 longitudinal rows of granules may be present, with 70 to 90 in the majority of specimens. There is therefore a greater range and higher average number of rows than in Powers' material, in which he recorded 52 to 60 rows. The very numerous, fine cilia and the large associated basal granules in fixed material, and the uneven movements of the living organism, lead Powers to deduce that compound cilia, possibly cirri or membranelles are present, and he illustrates this. He does not mention the possibility that both groups of cilia (compound cilia) and cirri may be present. We find that numerous, very fine cilia arise in groups from the large basal granules (Figs. 3 and 4), penetrate the pellicle through a single pore and then usually spread fanwise. These, we consider, are discrete, but compound cilia, not cirri or membranelles. The basal granules would of necessity be compound, through no indication, other than their large size, can be obtained. Each cirrus (Figs. 1 and 2) arises from the most posterior granule of each row. These granules appear, in both sections and whole mounts, to be squarish in outline and transversely elongated in contrast to the spherical or slightly longitudinally elongated granules of the ciliary groups. The cirri were evidently not detected by Powers, but in local material they lie close to the surface of the posterior portion of the body (Fig. 2). They are compact and solid structures at their point of origin, but they break into bundles of discrete cilia within a short distance of the origin. A ring of transversely elongate, minute granules (Fig. 2), much narrower than those of the cirri, is sometimes seen immediately anterior to the granules of the cirri. The significance of these granules could not be determined. Ciliary rootlets (neuromotor fibrils) extend into the surface of the endoplasm from the innermost portions of the basal granules. They can be seen in both transverse and longitudinal sections. Prolonged searching failed to disclose any longitudinal or transverse fibres. Some individual rootlet fibres, however, show small nodules at a regular depth below the basal granules (Fig. 4), and these may be the junctions of longitudinal and transverse fibres. The macro- and micronucleus of local individuals (Fig. 5a) are typically as Powers describes them, including the “extra-nuclear vesicles” which he reported. The macronucleus is slightly irregular in outline, sub-spherical to spherical, and contains a plastin core