A Monogvcq^li. of the Myxogastres. 7 



the crucial point in De Bary's characteristic Avork of separation, 

 which "lies in the formation of plasmodia or aggregation of 

 swarm-cells," it will be well to treat individually, all the points 

 embodied in the original, commencing with the coalescence of 

 cells. This coalescence, and consequent loss of individuality 

 of cells to form a common mass of protoplasm capable of 

 spontaneous movement, is the leading characteristic of a 

 Plasmodium ; but it is an undoubted fact that motility is to a 

 very considerable extent influenced by the presence or absence 

 of a cell- wall, or to the relative plasticity of the cell-wall Avhen 

 present; and coalescence of protoplasm, even when cell-walls 

 intervene, is highly characteristic of fungi, and has received differ- 

 ent names depending on its supposed morphological or physio- 

 logical functions; it is sufficient to name "clamp-connections" 

 characteristic of the vegetative hyphae of the Basidiomycctcs ; and 

 the complex irregular network formed by the vegetative hyphae 

 of many of the forms included in the Hypliomycetes as being due 

 to the fusion of portions of protoplasm originally distinct. In 

 the above examples the component hyphae are septate ; but in 

 the Mmorini, where the hyphae are entirely without septa, 

 there is a still nearer approach to a plasmodium. 



In the last-named group, the spore on germination gives 

 origin to an intricately branched mycelium, the component 

 branches of which eventually form a dense, irregular network, 

 due to the numerous points at which coalescence of originally 

 distinct branches has taken place. If single spores, picked up 

 under a low magnifying power, on the point of a needle touched 

 with glycerine, are sown on glass slips in a thin smearing of 

 sterilized decoction of raisins, covered with large squares of thin 

 glass sterilized by passing through the flame of a spirit-lamp, 

 raised at one end by a strip of tracing-paper to prevent crushing 

 the spore, and at once sealed up with cement, it will be found 

 that in most cases, spores of the Hypliomycctcs or Phycomycetcs Avill 

 germinate at once, and continue to grow until a considerable 

 mass of mycelium is formed ; such preparations can be examined 

 at any moment under high powers without loss of time, and 

 the behaviour of the mycelium followed. A noteworthy feature 



