MARINE BIOLOGICAL STATION ON PUFFIN ISLAND. 13 



Brittany coast, and made some very interesting observa- 

 tions and experiments at St. Malo with the acorn-shell, 

 Balanus halanoides, which is so commonly found at the 

 extreme upper edge of the littoral zone on rocky coasts. 

 Vaillant found that this marine animal, although it can 

 only expand and obtain food when covered with water, is 

 able to live so far above ordinary high-w^ater mark as to 

 remain dry for days at a time, amounting on an average 

 to eighteen or nineteen-twentieths of its life ; and he 

 determined by experiment that it can live out of w^ater for 

 at least forty-four days at a time. 



These observations are particularly interesting to me, 

 as, before hearing in Paris last summer of Vaillant's work, 

 I commenced some almost exactly similar observations at 

 Hilbre Island, in 1885* and at Puffin Island in 1887, 

 from which I made out that the Polyzoon Flustrella 

 hispida, which is found within a yard of ordinary high- 

 water mark, must be exposed to the air during about 

 five-sixths of its existence, and can only feed during the 

 remaining one-sixth at and about the time of high tide. 

 Probably respiration can be carried on to a certain extent 

 both in the case of this animal and of Vaillant's Balani 

 by a little air being let in periodically to oxygenate the 

 small quantity of sea-water shut in with the body of the 

 animal. 



Experiments on Harpacticid^. 



One of the first things one notices on examining the 

 zones of life upon the shore at Puffin Island is that there 

 are certain marine animals above high- water mark. There 

 are some pools in the rocks w^hich are only reached at high 

 spring tides, or perhaps only by the spray from the weaves 

 during storms. These are overgrown with a common 



* See Liverpool Daily Post, 15th June, 1885. 



