Vol. XLIV. May, 1923. No. 5. 



BIOLOGICAL BULLETIN 



STUDIES IN MARINE ECOLOGY: III. 



SOME PHYSICAL FACTORS RELATED TO THE 



DISTRIBUTION OF LITTORAL INVERTEBRATES. 



W. C. ALLEE, 



Marine Biological Laboratory and the University of Chicago. 



Page 



I. Purpose and scope of the investigation 205 



II. Methods 208 



III. Series of associations 209 



1. Associations of rocky eroding shores 210 



a. The open water association 210 



b. The wharf piling association 211 



c. The exposed rock association 215 



d. The protected rock association 219 



2. Associations of depositing shores 225 



a. The open water association 225 



b. The sand bar association 225 



c. The muddy sand association 227 



d. The eel grass and muck associations 228 



(1) The Cumingia association 229 



(2) The Scolopos acutus association 229 



e. The marginal muck associations 232 



/. The intertidal associations 234 



(1) The Mya association 234 



(2) The Melampus association 236 



IV. Summary of data 236 



V. Discussion 242 



VI. Bibliography 248 



I. Purpose and Scope of the Investigation. 1 



The first two papers in the present series give the results of a 

 general faunistic ecological survey of the Woods Hole littoral 



1 I am indebted to the Marine Biological Laboratory for facilities for carrying 

 on this survey and particularly to Mr. G. M. Gray for arranging for my comings 

 and goings. I am also indebted to Dr. P. H. Mitchell of the Bureau of Fisheries 

 for the loan of certified hydrometers and to Supt. W. H. Thomas for access to 

 manuscript notes of daily temperature and salinity determinations. 



205 

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