228 



W. C. ALLEE. 



eel grass. The effect of the eel grass on oxygen content and on 

 pH is noticeable although not so extreme as will be found later. 

 These effects are the expected result of photosynthesis. 



Table IX. 



Showing Analyses of the Water taken over the Muddy Sand or 

 Phascolosoma Association. 



Date 

 1920. 



Time. 



Depth 



Water 



Tide. 



Temp. 

 C 



pH. 



Bot. Sur. 



Coll. 



Northwest Gutter. 



Southwest Gutter Creek. 



8/25 



Gansett. 



78 

 78 

 80 



d. Eel Grass and Muck Associations. — The Associations of the 

 eel grass and muck lie between the last discussed habitat and a 

 region about a rod from the shore line of the type of flats under 

 discussion. There at a depth of about a foot at low tide, the 

 eel grass ends and the marginal muck association begins. Two 

 major recognizable associations occupy this region: that char- 

 acterized by the bivalve, Cumingia tellinoides, which may be 



1 Same at surface. 



2 23 at surface. 



