VIl] MYXOMYCETES. 205 



It would simplify nomenclature, and avoid the multiplication 

 of generic names, if the term Algites were applied to such algal 

 fossils from rocks of various ages as afford no trustworthy data 

 by which their family or generic affinity can be established. 



V. MYXOMYCETES (MYCETOZOA). 



This class of organisms affords an interesting example of the 

 impossibility of maintaining a hard and fast line between the 

 animal and plant kingdom. Zoologists and Botanists usually 

 include the Myxomycetes" in the text-books of their respective 

 subjects, and the name Animal-fungi which has been applied 

 to these organisms expresses their dual relationship. They 

 constitute one of three groups which we may include in that 

 intermediate zone or ' buffer-state ' between the two kingdoms. 

 From a palaeobotanical point of view the Myxomycetes are of 

 little interest, but a very brief reference may be made to them 

 rather for the sake of avoiding unnecessary incompleteness in 

 our classification than from their importance as possible fossils. 



They are organisms without chlorophyll, consisting of a 

 naked mass of protoplasm, known as the plasmodium, which 

 may attain a size of several inches. Such plasmodia creep 

 over the surface of decapng organic substrata, and in forming 

 their asexual reproductive cells they are converted into some- 

 what complex fruits containing spores. The spores produce 

 motile swarm-cells, which eventually coalesce together to form 

 a new plasmodium. 



A few examples of fossil Myxomycetes have been recorded 

 from the Palaeozoic and more recent formations, but none of 

 them are entirely beyond suspicion. We may mention three 

 examples of fossils referred to this group, but only one of these 

 is entitled to serious consideration. 



Myxomycetes Mangini Een.^ It is not uncommon to find 



1 An excellent monograph on the Mycetozoa has lately been issued by the 

 Trustees of the British Museum under the authorship of Mr A. Lister (94). Vide 

 also Sohroter (89) in Engler and Prantl's Naturlichen Pflanzenfamilien. 



2 Benault (96) p. 422, figs. 75 and 76. 



