INAUGURAL ADDRESS. 21 
possible injury by their calcareous armour, such as the 
Escharide and other relations of Lepralia, or else are well 
supplied with snapping sharp-beaked avicularia, such as 
the species of Bugula,* &c. Most of the other animals, 
which are defenceless, will be found to be either of quiet 
greys and browns or other dull shades, or to be protected 
by a marked resemblance in their colouring to the stones 
and sea-weeds on which they lie, or to some of the above- 
mentioned conspicuous animals which are able to take 
care of themselves. 
A few marked instances of this mimetic resemblance 
to other organisms have come under my notice. One of 
these was the case of a brilliant red Turbellarian worm 
(Leptoplana sp.?), which was found at Puffin Island 
creeping on the surface of a colony of Mucronella coccinea 
of the same colour; and several of the other Turbel- 
larians resemble the Compound Ascidians upon which 
they are found. Another example was a pinkish purple 
Amphipod (Calliopius norvegicus), which was exactly of the 
same tint as one of the encrusting Nullipores in the shore 
pools. I watched this animal for a considerable time one 
morning at Puffin Island, and found that in its many 
excursions about the pool it very rarely left the parts 
coloured like itself, and that when I removed it to a patch 
of bare rock it at once took refuge again on the protecting 
Nullipore. 
Another of the fundamentals of evolution which is well 
illustrated by the fauna of the Laminarian zone is 
“variation,” a subject which requires careful observation 
and experiment as much as any in the wide range of 
Biology. It is most important, on account of the obvious 
bearing upon species, that we should know something of 
* The orange-coloured Bugula turbinata is certainly one of the most 
conspicuous animals about low water mark at Puffin Island. 
