340 150TANV 



,Mi>t representatives of the group live as naked, free cells ; others form more 

 or less complicated cell-colonies held together by mucilage, or they possess peculiar 

 stalked or uustalked firm investments. 



Sexual reproduction is wanting. Multiplication takes plaee by longitudinal 

 division, and in many species thick-walled resting spores or cysts are produced. 



Euyli'H" ' Kig. 264) may be taken as an example. The speeies live in water 

 containing organic substances and often appear in large numbers. By varying 

 I lie nutritive conditions colourless forms \\itli reduced chnmiatoplimes are 

 obtained ( 8 ). 



CLASS IV 

 Myxomycetes (Slime-Fungi) ( !> ) 



The Myxomycetes form an independent group of lower Thallo- 

 phytes ; in certain respects they occupy an. intermediate position 

 between plants and animals, and have in consequence also been termed 

 Mycetozoa or Fungus-animals. They are represented by numerous 

 species, and are widely distributed over the whole earth. In their 

 vegetative condition the Slime-Fungi consist of naked masses of proto- 

 plasm, the FLASMODJA, containing numerous small nuclei but utterly 

 devoid of chlorophyll. Glycogen occurs as a reserve substance, while 

 starch is not found. The plasmodia (p. 54) are found most frequently 

 in forests, upon soil rich in humus, upon fallen leaves, and in decaying 

 wood. They creep about on the substrata, changing their form at the 

 same time, and thrust out processes or pseudopodia, which may in 

 turn coalesce. At the period of spore-formation the plasmodium 

 creeps out from the substratum towards the light and air, and, after 

 coming to rest, is converted into single or numerous and closely 

 contiguous fructifications, according to the genus. On the periphery 

 of each fructification an outer envelope or I'KRIDIUM is formed ; while 

 internally the contents of the fructification separate into spores, each 

 of which is. provided with a nucleus, and enclosed by an outer wall. 

 The isolation of the spores may take place on the conclusion of cell 

 divisions (Trirhia) ; in other cases (e.g. Fuligo) the plasmodium divides 

 into a number of multinucleate portions while nuclear division is in 

 progress, and these portions subsequently divide, giving rise to 

 the spores. The spores thus formed have accordingly an asexual 

 origin. In many genera, part of the internal protoplasm within the 

 SPORANGIUM or spore-receptacle is utilised in the formation of a 

 CAPILLITIUM (Fig. 266 />'), consisting of isolated or reticulately 

 united threads or tubes. Upon the maturity of the spores, the 

 peridium of the sporangium becomes ruptured, the capillitium expand.- 

 (Fig. 265 J5), and the spores are dispersed by the wind, aided by the 

 hygroscopic movements of the capillitium. In the case of the genus 

 i 'iTiifiomi/.ra, the process is somewhat simplified, as the fructification 

 is not enveloped by a peridium, and the spores are produced at the 



