STUDIES IN MARINE ECOLOGY. 



233 



vegetation and with a bottom of soft muck some eight inches or 

 more deep. The Thyone bury themselves in this muck, leaving 

 only the tentacles and cloacal opening exposed. They are 

 frequently numerous and may be seen over considerable extent 

 with one or more for every square yard. 



Associated with Thyone briareus, in such locations are: a few 

 of the worms, Clymenella; many Lumbrinereis tenuis, and the 

 clam- worm, Nereis virens. 



Of the Crustacea, Carcinides mcenas, the green crab, is most 

 conspicuous and may frequently be seen running along the 

 bottom, dodging in and out of the eel grass. The ever-present 

 small hermit crabs, P. longicarpus, with their usual commensals, 

 are present in some abundance together with the shrimp, Crangon 

 vulgaris. The mud crab, Panopeus, is also found. 



The molluscs are represented by Modiolus demissus, near the 

 edge, where My a and Venus also occur. There are also a few 

 strings of Mytilus edulis and some rolls of Crepidula fornicata to be 

 found. Mud snails, N. obsoleta, are also present. 



Table XI. 



Showing the Results of Analyses of the Water over the 

 Thyone Association. 



All but the last two items are from NW. Gutter Flats; those are from Blind 

 Gutter Flats. 



B, collection from bottom; S, collection from surface. 



