MARINE BIOLOGICAL STATION AT PORT ERlN. 29 



sidered established beyond doubt ; and that the illuminated 

 tow-net can be used in at least moderately deep water was 

 evident to all who saw the success with which the net was 

 worked on board the " Hyaena " in thirty fathoms. 



In this year (1889) the second volume of the " Fauna " 

 appeared containing reports on various groups, from Diatoms 

 up to Seals and Cetaceans, including the description of several 

 Invert ebrata new to science. 



In this year, also, we continued the observations on the 

 "zoning of the shore"— that is, the distribution of charac- 

 teristic animals and plants in relation to high and low water 

 levels and depths below low water mark— which we had 

 started at Hilbre Island in 1885 and at Puffin Island in 1887. 

 and which leads to some curious results such as that the 

 Polyzoon Flustrella hispida, found within a yard of average 

 high water, is exposed to air during about five-sixths of its 

 existence and can only feed and expand during the remaining 

 one-sixth at and about the time of high tide ; and that the 

 common rock barnacle, Balanus balanoides, is able to live so 

 far above ordinary high water mark as to remain dry for days 

 at a time amounting to eighteen or nineteen- twentieths of its 

 life. Observations were also made on certain other marine 

 animals which can live above high water mark, such as the 

 Copepod Harpacticus fulvus and the Gastropod Mollusc 

 Littorina rudis. 



Other notable fentures of the work during 1889 were 



(1) the experiments with Mr. Hoyle's deep-sea closing tow-net 

 designed to capture the plankton in certain limited zones of 

 water intermediate between the bottom and the surface ; 



(2) observations on the structure and function of the bighly- 

 coloured processes or cerata projecting from the body of 

 Nudibranchs such as Dendronotus, Tritonia, Dolo and Eolis, 

 and their usefulness as protecting or Warning characters — this 

 matter was continued on future occasions and the results were 



