THE KINGDOM PROTISTA. 49 



1. The still living Monera ; 2. The Amoeboidea, or Protoplasts ; 

 •3. The Whip-swimmers, or Flagellata; 4. The Flimmer-balls, 

 or Cataliacta; 5. The Tram-weavers, or Labyrinthuletv ; 

 6. The Flint-cells, or Diatomeee ; 7. The Slime-moulds, 

 or Myxomycetes ; 8. The Ray-streamers, or Rhizopoda. 



The most important groups at present distinguishable in 

 these eight classes of Protista are named in the systematic 

 table on p. 51. Probably the number of these Protista 

 will be considerably increased in future days by the pro- 

 gressive investigations of the ontogeny of the simplest forms 

 of life, which have only lately been carried on with any great 

 zeal. With most of the classes named we have become 

 intimately acquainted only during the last ten years. The 

 exceedingly interesting Monera and Labyrinthulese, as also 

 the Cataliacta, were indeed discovered only a few years ago. 

 It is probable also that very numerous groups of Protista 

 have died out in earlier periods, without having left any 

 fossil remains, owing to the very soft nature of their bodies. 

 We might add to the Protista from the still living lowest 

 groups of organisms — the Fungi ; and in so doing should 

 make a very large addition to its domain. Provisionally we 

 shall leave them among plants, though many naturalists 

 have separated them altogether from the vegetable kingdom. 



The pedigree of the kingdom Protista is still enveloped 

 in the greatest obscurity. The peculiar combination of 

 animal and vegetable properties, the indifferent and un- 

 certain character of their relations of forms and vital 

 phenomena, together with a number of several very peculiar 

 features which separate most of the subordinate classes 

 sharply from the others, at present baffle every attempt 

 distinctly to make out their blood relationships with one 



VOL. II. E 



