226 



W. C. ALLEE. 



List 6. Characteristic Animals of the Sand Bar Association. 



Ccelenterata: 



Hydractinia echinata on shells oc- 

 upied by P. longicarpus. 



Nemertini: 



Cerebratulus lacteus, 

 Micruri leidyi. 



Echinoderma: 



Leptosynapta inharans. 



Annelida : 



Clymenella torquata, 

 Diopatra cuprea, 

 Phyllodoce sp., 

 Scoloplos fragilis, 

 Scoloplos robustus. 



Arthropoda : 



Crangon vulgaris, 

 Ovalipes ocellatus, 

 Pagurus longicarpus, 

 Limulus polyphemus. 



Mollusca: 



Crepidula convexa, on hermit crab 



shells, 

 Crepidula plana, on hermit crab 



shells, 

 Ensis directus, 

 Nassa trivittata, 

 Natica duplicate with egg collars. 



Chordata : 



Dolichoglossus kowalevskyi, 



The conditions of the water over this association are shown in 

 Table VIII. The last item in the table was from Blind Gutter 



Table VIII. 



Showing Temperature, Salinity, Oxygen Content and pH of Sea 

 Water over the Sand Bar Association. 



Bar. The others are from Northwest Gutter Bar. With the 

 exception of one reading, made in triplicate, the pH ranges from 

 8.0 to 8.25. In this respect it approaches open water. The 

 observed range is greater than that of the nearby rocks. The 

 salinity is similar to that of the rocks and less than that of the 

 open water. The oxygen content resembles that of exposed 

 rocks where rockweeds are absent. The temperature range is 

 greater than in any other association so far studied and the 



1 Blind Gutter Bar. 



