. A monograph of the Mycetozoa, being a descriptive catalogue of the species in the herbarium of the British Museum. Illustrated with seventy-eight plates and fifty-one woodcuts. Myxomycetes. INTRODUCTION. 13 formed. The chromatin constituents of the nucleus first show a coarser arrangement, which is followed by the " spindle stage," exhibiting an equatorial plate with achromatic fibres converging at the poles. In Badhamia, Physa/nim, Graterivm, Didymium, Steinonitis, Lamproderma, and Comatricha the plasma at this period breaks up into lobed masses containing six to ten nuclei; the e
. A monograph of the Mycetozoa, being a descriptive catalogue of the species in the herbarium of the British Museum. Illustrated with seventy-eight plates and fifty-one woodcuts. Myxomycetes. INTRODUCTION. 13 formed. The chromatin constituents of the nucleus first show a coarser arrangement, which is followed by the " spindle stage," exhibiting an equatorial plate with achromatic fibres converging at the poles. In Badhamia, Physa/nim, Graterivm, Didymium, Steinonitis, Lamproderma, and Comatricha the plasma at this period breaks up into lobed masses containing six to ten nuclei; the equatorial plate of each nuclear spindle now divides horizontally, and as the two halves draw apart the lobed masses of plasma undergo a further division, untU the time when the daughter- nuclei have widely separated. Though stUl connected by achro- matic^ fibres, each pair is enclosed in a portion of plasma of the capacity of two spores; these portions become constricted into the ultimate spores, each containing a single nucleus : in a short time the spore wall is acquired, and the active stage of the organism comes to a close. In the genera just mentioned, spore- formation occurs in warm weather about twenty hours after the sporangia have taken form. In Trichia tHe in- terval is much longer, ex- tending from two to four days according to the tem- perature. In this genus and also in Arcyria, Lycogala, and Reticula/ria Lycoperdon, the spore-plasm is not seen to separate in lobed masses at the time when the nuclear spindle is formed, but the karyokinetic pro- cess is completed and the daughter - nuclei are de- finitplv nartpd frnm otih ^""^ * stained preparation o£ a young spor- nniieiy partea irom one anglum, showing the plaamodium separated into another before the plasma masses of two spores' capacity round the nuclei, 1 1 _ J i 1 which have almost diTided by karyokinesiSi breaks up and encloses each Magnified 1200 times. nucleus in a young spore.* The sporophores of
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Keywords: ., bookcentury1800, bookdecade1890, booksubjectmyxomyc, bookyear1894
