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N2.1II.9. MYCETOZOA. BADHAMIA UTRICULARIS Berk. Plasmodium spreading on glass, stained with picrocarmine, magnified 15 times. of the same, showing nuclei, magn A MONOGRAPH OF THE MYCETOZOA BEING A DESCEIPTIYE CATALOGUE OF THE SPECIES IN THE HERBARIUM OF THE BRITISH MUSEUM. ILLUSTEATED WITH SEVENTY-EIGHT PLATES AND FIFTY-ONE WOODCUTS. BY AETHUE LISTEE, E.L.S. LONDON: PRINTED BY ORDER OF THE TRUSTEES. SOLD BY LONGMANS & CO., 39 PATEBNOSTEE BOW; B. QUABITCH, 15 PICCADILLY; DULAU & CO., 37 SOHO SQUABE, W. ; KEGAN PAUL, TBENCH, TRUBNEB, & CO., 57 LUDGATB HILL; AND AT THE BBITISH MUSEUM (NATUBAL HISTOBY), CEOMWELL BOAD, S.W 1894. PEEEATOEY NOTE. HHHE collection of specimens of Mycetozoa in the -•- Herbarium of the British Museum has been greatly increased in recent years. The additions include the large collection of the late G. E. Broome, bequeathed by him to the Museum, and that of H. W Ravenel, purchased from his widow. It was necessary to make a critical examination of the whole of the materials in the Herbarium. Mr. Arthur Lister, who has devoted much attention to these organisms, was fortunately able to undertake this work; and he agreed at the same time to prepare a monograph of the whole class based on this examination. This volume, the result of his labours, contains descrip­ tions not only from the specimens in the Museum, but also from types in various public and private Herbaria, and from his own rich collection. Mr. Lister has generously presented a large series of specimens to the Museum, so that the Herbarium now contains types of all the species described by him in this monograph. The volume is fully illustrated with plates mechanically reproduced from faithful water-colour drawings by the author and by his accomplished daughter, to whom in the Introduction Mr. Lister acknowledges his obligations. WILLIAM GARRUTHERS. November, 1894. CONTENTS. INTRODUCTION 1 SYNOPSIS OF THE ORDERS AND LIST OF THE GENERA 21 DESCRIPTIONS OF THE GENERA AND SPECIES 25 INDEX 213 LIST OF PLATES 221 INTKODUCTION. FRIES gave the name of Myxogastres, in 1833, to the group of organisms described in this Monograph, placing it among the Gasteromycetous Fungi. In 1836 Wallroth substituted the term Myxomycetes (Schleimpilze) for the older name, and this came to be the generally accepted designation. Later investigations showed that the spores, instead of producing a mycelium, as in the case of fungi, gave birth to swarm-cells, which coalesce to form a Plasmo­ dium. In consequence of this discovery, which indicated a relation­ ship with the lower forms of animal life, de Bary in 1858 introduced the name Mycetozoa. Under this head he still retained the term Myxomycetes for the section so named by Wallroth, but linked with them the Acrasiece of Van Tieghem, a small group inhabiting the excrement of animals; in these the spores are said to produce swarm-cells, as in the Myxpmycetes, which multiply by division but do not coalesce to form a plasmodium. At a certain period, when the fruits are about to be formed, they become attached in branching strings which concentrate to a point, where they are massed together in aggregations of more or less definite shape; the swarm-cells, however, do not lose their individuality. In Dictyostelium, a genus of the Acrasiece, a stalk is formed by the arrangement of a number of swarm-cells in vertical rows in the centre of the heap; the surrounding amoeboid bodies creep up this stalk and form a globose cluster at the extremity; here each amoeboid swarm-cell acquires a spore-wall, and they become a naked aggregation of spores not enclosed by a definite sporangium- wall. Rostafinski followed de Bary in the view that the formation of a plasmodium indicates a wide separation in the natural position of the Myxomycetes from the fungi, but he suppressed that name entirely, adopting de Bary's class name Mycetozoa in its place; at the same time, he admitted into his Monograph Dictyostelium, a genus of the Acrasiece. The reason for his including this genus may be the fact pointed out by de Bary, that Brefeld in first describing the dense aggregations of swarm-cells into the stalked spore-masses of Dictyostelium, refers to them as being " plasmodia; that is, products of the coalescence of swarm- cells ; " and it was not until after the publication of Rostafinski's 1 INTKODUCTION. FRIES gave the name of Myxogastres, in 1833, to the group of organisms described in this Monograph, placing it among the Gasteromycetous Fungi. In 1836 Wallroth substituted the term Myxomycetes (Schleimpilze) for the older name, and this came to be the generally accepted designation. Later investigations showed that the spores, instead of producing a mycelium, as in the case of fungi, gave birth to swarm-cells, which coalesce to form a plasmo­ dium. In consequence of this discovery, which indicated a relation­ ship with the lower forms of animal life, de Bary in 1858 introduced the name Mycetozoa. Under this head he still retained the term Myxomycetes for the section so named by Wallroth, but linked with them the Acrasiece of Yan Tieghem, a small group inhabiting the excrement of animals; in these the spores are said to produce swarm-cells, as in the Myxpmycetes, which multiply by division but do not coalesce to form a plasmodium. At a certain period, when the fruits are about to be formed, they become attached in branching strings which concentrate to a point, where they are massed together in aggregations of more or less definite shape; the swarm-cells, however, do not lose their individuality. In Dictyostelium, a genus of the Acrasiece, a stalk is formed by the arrangement of a number of swarm-cells in vertical rows in the centre of the heap; the surrounding amoeboid bodies creep up this stalk and form a globose cluster at the extremity; here each amoeboid swarm-cell acquires a spore-wall, and they become a naked aggregation of spores not enclosed by a definite sporangium- wall. Rostafinski followed de Bary in the view that the formation of a plasmodium indicates a wide separation in the natural position of the Myxomycetes from the fungi, but he suppressed that name entirely, adopting de Bary's class name Mycetozoa in its place; at the same time, he admitted into his Monograph Dictyostelium, a genus of the Acrasiece. The reason for his including this genus may be the fact pointed out by de Bary, that Brefeld in first describing the dense aggregations of swarm-cells into the stalked spore-masses of Dictyostelium, refers to them as being " plasmodia; that is, products of the coalescence of swarm- cells ; " and it was not until after the publication of Rostafinski's 1 2 INTRODUCTION. Monograph that Van Tieghem in 1880 and Brefeld in 1884 corrected this view. Accepting the Mycetozoa as established by Rostafinski, but excluding Dictyostelium on the ground of its not forming a *true plasmodium, we have a clearly defined group of organisms sepa.ua/ed from all others by the following combination ot characters. A spore provided with a firm wall produces on germination an amoeboid swarm-cell which soon acquires a ilagellum. The swarm-cells multiply by division and subsequently coalesce to form a plasmodium which exhibits a - rhythmic streaming. The plasmodium gives rise to fruits which consist of supporting structures and spores; in the Undosporeos these have the form of sporangia, each having a wall within which the free spores are developed. A capillitium or system of threads forming a scaffolding among the spores is present in most genera. In the Exosp)orece the fruits consist of sporophores bearing numer­ ous spores on their surface. Hie Spore and Swarm-cell.—The spores of the Endosporece are mostly spherical, but occasionally they are ellipsoid. Their size is uniform in each species, or with so little variation that their measurement affords a valuable character for specific determination. This is not without exception; for instance, in the abubdant species Leocarpus fragilis the spores are commonly 11 to 12 p diameter, but in occasional gatherings they average 16 to^O p. In other genera which present ample material for comparison, similar variation is sometimes met with. The sporejwa'll is variously coloured in the different species. It is described by Zopf as showing the chemical reaction of cellulose^ and consisting of a simple firm membrane; * but the spores of several species of Didymium and Trichia, when crushed in an acetic solution of gentian-violet, show the existence of two layers, the inner more delicate and appearing less deeply stained than the outer. In Physarum, Arcyria, and genera with thin-walled spores, the double layer has not been traced. It is either smooth or marked with sculpture. The contents of the spore consists of faintly granular protoplasm with a single central nucleus. In abnormal developments, monstrous spores, often of irregular shape and containing several nuclei, are of frequent occurrence. The length of time that elapses before the germination of the spore after it has been placed in water varies with the species, and often in different gatherings of the same species. In the darker spores of Stemonitis fusca it does not begin for nine or twelve hours, while in the pale-spored variety it has been observed to occur in twenty-eight minutes. In Reticularia Lycoperdon it usually takes place in less than an hour in fresh gatherings; spores from a specimen which had been stored for nearly three years began to germinate in four hours, and in twenty hours nearly every spore had done so. Didymium difforme * Schenk, " Handbuch der Botanik"," Bd. iii. 2, 1884 : " Die Pilzthiere " p.

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