. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . d substances. With iodine and sulphuric acid the wall colours only a golden yellow. The building-up and the strengthening of the walls and trabeculse of Caulerpa havefurnished much evidence in favour of the growth of cell-walls by apposition. The protoplasm is disposed as a parietal layer on the inner side of thewall, and it also covers all the trabeculse, numerous anastomosing strandspassing from the thin layer around each of the trabeculas
. Algæ. Vol. I. Myxophyceæ, Peridinieæ, Bacillarieæ, Chlorophyceæ, together with a brief summary of the occurrence and distribution of freshwat4er Algæ . d substances. With iodine and sulphuric acid the wall colours only a golden yellow. The building-up and the strengthening of the walls and trabeculse of Caulerpa havefurnished much evidence in favour of the growth of cell-walls by apposition. The protoplasm is disposed as a parietal layer on the inner side of thewall, and it also covers all the trabeculse, numerous anastomosing strandspassing from the thin layer around each of the trabeculas to the peripheralparietal layer. Most of the strands run more or less longitudinally, and it isnot unlikely that one function of the trabeculoe is to give support to thisdelicate anastomosis of protoplasmic strands. In short, without this supportit would scarcely be possible for the delicate protoplasmic threads to ramifythrough the large central vacuole of the coenocyte. Numerous nuclei arepresent everywhere through the protoplasm, and there are also numerousdisc-shaped chloroplasts, mostly aggregated in the peripheral layer. The Caulerpaceae 231. Fig. 151. A, longitudinal section of tbe leafof Caulerpa prolifera (Forsk.) Lamx., tt,transverse trabeculae ; It, longitudinal trabe-cula?; x about 80 (after Oltmanns). B, trans-verse section of stem of Caulerpa Holmes-iana G. Murray, x about 40 (after G. Murray). chloroplasts, which are without pyrenoids, are according to Mme Weber van Bosse in some species relatively large. The peripheral layer of protoplasm is for the most part quiescent, but the more central anastomosis exhibits an upward and downward streaming movement which caused Janse (90) to regard the streams as nutritive in character. There are no reproductive organsin Caulerpa, propagation taking placeonly by the separation of proliferousshoots. This is very well seen inCaulerpa prolifera, a species which is frequent in the Mediterranean,preferring deep water and sh
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