CHAPTER XXVIII. 



BIONOMIC CHARACTERLSTICS OF PLANTS AND ANIMALS. 



A bionomic consideration of the different classes of modern 

 plants and animals is of the utmost importance to the stratigrapher, 

 since it is from such studies that he is enabled ta interpret the 

 conditions of the past, in so far as they are indicated by organisms. 

 The present chapter will, therefore, deal somewhat at length with 

 the bionomic characters of the various classes, special stress being 

 laid on those types which are capable of fossilization. 



BIONOMIC CHARACTERS OF PLANTS (Schimper-25). 



Protophyta. 



The majority of these primitive plants are not adapted for 

 preservation, and hence are unknown in the fossil state. The slime 

 molds, or Myxomycetes, occur on decaying logs, in damp wood, on 

 rotting leaves, etc. The Schizophytes or bacteria are every- 

 where present. They are abundant in the plankton of the shallower 

 portions of the sea, but rare in the open sea. In fresh water, in 

 the air, and in the soil, as well as in all decaying substances, they 

 occur, themselves forming the principal agents of decay. Their 

 work in the formation of iron ore deposits has elsewhere been re- 

 ferred to. The Cyanophycege occur in the sea, in fresh water, on 

 moist earth, on damp rocks, and on the bark of trees. They enter 

 the intercellular spaces of higher plants, and may enter into the 

 structure of the lichen thallus. Some species flourish in hot springs 

 with a temperature as high as 85° C. Volvox and other flagellates, 

 most of which are generally regarded as animals, are especially 

 at homie in stagnant water, and amidst putrefying organic matter in 

 the sea or in fresh water. Many flagellates are also parasitic and 

 the spores of some may survive a temperature of 250° to 300° F. 

 for ten minutes, though the adults are killed at 180°. 



