1 86 W. C. ALLEE. 



Table II. 



Relation of Different Habitats Based on Distribution of 

 Characteristic Animals. 





The association of the wharf pilings is found to be closely 

 related with that of the rocks; Jj per cent, of the animals 

 common in the former are next most abundant in the latter. 

 This fits with one's general impression that the two sets of animals 

 are much the same but with the emphasis placed on different 

 species so far as numbers are concerned. 



The animals common on the rocks are next most abundant on 

 the pilings but almost as many are nearly as abundant on the 

 flats. The latter is to be expected from the fact that the rocks 

 extend up from the flats, often forming a belt only a few feet 

 wide in the intertidal portion of the flats, and that single rocks 

 frequently occur surrounded by typical mud or sand flats, and 

 from the further consideration that the eel grass offers almost as 

 good a place of attachment for many animals as do the rocks. 



The animals taken commonly in dredging are more closely 

 related to the rock association than to the others. This is because 

 our dredging operations have been done on clean hard bottom 

 where the water conditions are similar to those found among 

 rocks. Dredging in mud as in Buzzards Bay would give different 

 results and transition bottom associations are indicated from the 

 dredging work in Great Harbor. 



Again the marked independence of the flats as a special habitat 

 is shown by the larger number of animals frequently taken there 



1 Where animals are approximately equally distributed between two different 

 associations they are summarized by fractional representation. 





