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 eyi- 
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 nudibranchs offered to the fishes 
is:—Dendronotus, Doris, Ancula, and Holis: Holis bemg 
the most distasteful form, Ancula next, JJoris less so, and 
Dendronotus edible, but from its size offering difficulties 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. Bateson’s interesting paper on ‘‘The Sense-organs and Perceptions 
of Fishes,” in the last number of the Jour. Mar. Biol. Assoc., dated April, 
1890, which however only reached Liverpool on May 14th, has appeared 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 by 
sight, the 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 their habits like the rockling 
described (p..238). by Mr. Bateson. 
