THE KINGDOM PROTISTA. 49 
1, The still living Monera ; 2. The Amceboidea, or Protoplasts ; 
3. The Whip-swimmers, or Flagellata; 4. The Flimmer-balls, 
or Catallacta; 5. The Tram-weavers, or Labyrinthulee ; 
6. The Flint-cells, or Diatomez; 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- 
yressive 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 Labyrinthulez, as also 
the Catallacta, 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 or 
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 
