1 88 EXPERIMENTAL EVOLUTION LECT. 



died. The other species were doing quite well ; both 

 are shore-inhabiting animals, while Sagartia lives 

 at some depth in the sea. 



In another experiment, I used animals of very dif- 

 ferent groups Carcinus maenas, Pagurus Prideauxii, 

 Dromia vulgaris, Anthea Cereus, Sagartia para- 

 sitica, Portunus puber, Doris tuberculata^ Venus (sp. ?), 

 Actinia mesembryanthemum, Holothuria cucumaria, 

 Grapsus (sp. ?) beginning with fresh water 20, and 

 sea water 70. 



I gradually altered the proportions, so that on the 

 thirty-fifth day I had 80 fresh water and 10 salt 

 water. I cannot go into details of this experiment, 

 or record the obituary of the different animals as 

 they one by one died, dreaming doubtless of shores 

 where experimenting bipeds are not admitted ; but 

 the final result was, that on the thirty-eighth 

 day I had nine animals living, of which eight 

 were Actinia mesembryantJiemum, and one Carcinus 

 maenas. While all my Anthea died, as also my 

 Sagartia (the latter opening the march), I did not 

 lose one single Actinia mesembryantkenmm. As all 

 are aware, this species, as well as the Carcinus 

 maenas^ lives as close as possible to the shore and 

 to the surface, so that, in fact, both must certainly 

 in their normal habitat have become accustomed to 

 a decrease in the saltness of the water. I have wit- 



