Synchronous zooid formation in Uiva pertusa Kjellman was induced in excised disks maintained in sterilized seawater at 20X, 12:12 h L: D cycle and fluorescent light at 100 |xmol photons m ^ S"^ Zooids were reieased from mature disk tissue on the morning of the second or the third day after excision. The degree of zooid formation was found to be dependent on disk size and the region of the mother thalius from which the disk tissue was excised. Zooid formation was induced in more than 90% of small disks (0.9 mm in diameter) which were taken from the margins of the Uiva thalii. When disks were incubated together with a perforated mother thalius, the disks remained sterile. The presence of maturation inhibitors in vegetative thalli is suggested.

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Constituents of fragrant subtidal red algae on Amami Island coasts were investigated, and the structures of several halogenated monoterpene compounds(II-XII) have been established.Halogenated monoterpene compounds 1) (II-XII) , have been found from red algae, Desmia hornemanni Mertens [Chondrococcus hornemanni (Mertens) Schmitz] (Japanese name "hosobanaminohano") together with myrcene (I ) and methyl palmitate. In this paper we wish to report the structure elucidation of the isolated compounds (II-IX) and also structure estimation of a few minor components (X-XII).The fresh red algae (500 g), have been extracted with methanol (1.51) for three days at room temperature.The extract was concentrated in vacuo and then extracted with hexane. After evaporation of the solvent the residue was separated into the two fractions eluted successively by hexane (1020 mg) and benzene (290 mg) through a column of silica gel (20 g). The fraction eluted by hexane had characteristic odor of the red algae and concerned to this communication. Separation of each constituent was carried out by preparative gas chromatography (carbowax-20M, MS and NMR spectra of the related compounds are listed for comparison (Table 1 and 2). The contents were calculated from the gas chromatogrammn (HB 2000, 0.25 mm Compound II, a major fragrant oil (75.4% of the volatile oil), M+ , m/e 170 and 172 (C10H15Cl), in hexane), was easy to polymerize in the air. Dehalogenation of II with NaBH4 in methanol gave myrcene (I) in 40% yield after 8 hrs ref lux, which was identified by comparison of the physical data with those of the authentic sample. IR, UV, WAR, and MS spectra of II exhibited the presence of an isopropylidene group, and a conjugated system consisting of two terminal methylenes, wherein no signal of AMX spin system indicated that a vinyl proton at C7 in the structure I was substituted by a chlorine. Indeed, protons close to chlorine absorbed at lower field (the differences were 0.59 ppm at C8Ha and 0.41 ppm at CIOHc) than those of myrcene. Thus, the chloride II must be 7-chloromyrcene.IR spectrum of III showed a striking resemblance to that of II. The MS spectrum of III was also similar to that of 11 except the fragments of M+ (m/e 214, 216) and M-43 (m/e 171, 173) depending on the difference of halogen atoms (Br and CI). NMR spectrum of III indicated the bromine substituent taking the place of chlorine in II.

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Summary. The preferential destruction of chloroplast nucleoids in young zygotes in the coenocytic alga Dictyosphaeria cavernosa and the giant unicellular alga Acetabularia calyculus was studied by high resolution epifluorescent microscopy. The chloroplast nucleoids (DNA) in the chloroplast from one of the parents were preferentially destroyed soon after the mating of male and female gametes.

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