THE SIMPLEST FORMS OF LIFE 45 
doubted progenitors of the higher plants, their evident 
relationship with the Volvocinez points to the latter as 
the starting point for the whole series of green plants 
above the Schizophycee. 
SUMMARY 
We have seen that at the bottom of the two great 
series of organisms — plants and animals— there is an 
assemblage of extremely simple forms, many of which 
have not reached a stage of differentiation where it is 
possible to say that they are either plant or animal. 
Of these the Slime-moulds and Monera represent two 
evidently related branches of a common stock, which is 
perhaps, on the whole, more animal than vegetable in 
its nature. The slime-moulds, however, owing to their 
aerial habits have developed fructifications which super- 
ficially closely resemble the sporangia of many higher 
plants, and the spores are also plant-like in character. 
These spores on germinating give rise to uniciliate, 
monad-like zodspores, which closely resemble the lower 
flagellate infusorians and suggest a relationship with 
them. The relationship of the slime-moulds to the 
other plants must be considered extremely doubtful. 
The second group of low plants, the Schizophytes, 
while certainly to be considered as plants, are neverthe- 
less very widely separated from any forms above them, 
and their connection with these higher plants must 
also be considered as, at least, uncertain. Whether 
the forms with chlorophyll among the Schizophytes are 
to be considered as the primitive types from which the 
bacteria or those forms without chlorophyll have been 
