Periodical Literature 113 



By combining all the animal forms which live under the same 

 life conditions, such as a forest type at one and the same period 

 of the year offers, he hopes to secure principles for the biology 

 of the forest fauna. 



The elements of such ethological system are: 



1. The influences which the condition of the soil of a given 

 site exercise ; 



2. The influences of humidity, free water and soil water, modi- 

 fied by site and weather conditions in different seasons; 



3. The influences of air, temperature, hght, also changing 

 with the season ; 



4. The influences which vegetation exercises, on one hand 

 depending on the same factors which are determinative for the 

 fauna, but nevertheless forming an independent factor in the 

 development of the flora. 



The author then enumerates forest types and locality types, 

 each of which would present different faunas, in part consisting 

 of elements which in the particular site are always and per- 

 sistently present, and in part only temporarily, changing with 

 the season. 



In every such habitat the elements of the fauna are again 

 differently distributed, and e. g. in the forest can be classified 

 according to their existence in certain layers. 



Such characteristic groups are: 



I. Animals of the soil (terricol fauna) : 



a.) All animals living underground; 



b.) The species living on roots; 



c.) Inhabitants of humus; 



d.) Those living in the litter. 



11. Animals of the soil flora and undergrowth : 



a.) 'Most larger game animals; 



b.) Reptiles and amphibians of the forest; 



c.) Gastropoda (snails) ; 



d.) Insects of soil fauna and undergrowth; 



e.) Spiders and other small animals. 



III. Animals which inhabit the trees above ground: 



a.) Ornis (birds) ; 

 b.) A few mammals; 

 c.) Insects: 



/.) On trunks; 



2.) In the wood; 



3.) In the crown. 



