160 LIVERPOOL BIOLOGICAL SOCIETY. 



swam up and looked or smelled at them but did 

 not touch them. 



The action of the large sole in bolting Doris No. 2 above 

 may possibly be explained as a result of the habits of com- 

 petition for their food. Three or four other fish were 

 darting at the nudibranch and the sole took the only 

 possible course by which it could secure the prey ; it made 

 a rapid movement upwards between the snouts of its com- 

 petitors and swallowed the Doris entire ; there was evi- 

 dently no time for examination. 



These experiments are manifestly incomplete and must 

 be largely added to in the future, but we believe it may be 

 useful to publish them at this stage, especially as we would 

 be glad of suggestions from any other biologists working 

 on the same lines.* Our general impression is that the 

 order of edibility of the nudibranch s offered to the fishes 

 is: — Demlronotas, Doris, Ancula, and Enlis : Eolis being 

 the most distasteful form, Ancula next, Jh)ris less so, and 

 Deudronotus edible, but from its size offering difiiculties to 

 the rather small fishes which we tried. 



We have used altogether fifty-three nudibranchs, offered 

 to twelve different kinds of fish and other voracious 

 animals, and we have recorded over a hundred and thirty 

 distinct transactions between the fishes and the nudi- 



* Mr. Batesoii's interesting paper on "The Sense-organs and Perceptions 

 of Fishes," in the last number of the Jour. Mar. BioL Assoc., elated April, 

 1890, which however only reached Liverpool on May 14th, has a})peared since 

 our paper was read (May 9th) and just as we are passing it for press. In 

 regard to the sole being one of those fishes which hunt for their food and re- 

 cognise it by the sense of smell alone, we would remark that the specimens in 

 the Aquarium here certainly seem to perceive their food as the plaice do liy 

 sight, tlie two kinds of fish often darting together at a food morsel — and, as 

 has just been shown above, the sole being sometimes more alert than its com- 

 petitors. Possibly these soles have changed tlieir habits like the rockling 

 described (p. 238) l)y Mr. Bateson. 



