78 
this is well known and familiar to everybody, who has only the 
slightest acquaintance with marine biology, I cannot omit men- 
tioning a special case observed in Japan. Among the Corallines 
growing on the rocks at Misaki, near low water mark, there was 
found living a Caprellid which resembled the rather broad and 
flattened branches of a certain species of Corallina to such degree, 
that it was no less amazing than the most perfect wandering stick 
among Phasmids. Its body and limbs were, of course, flattened in 
the same way as the Corallina-branches; that also the colour was 
exactly the same as that of the Corallina, needs hardly be stated. 
That numerous cases of protective resemblance are to be found 
especially among the Amphipods, I have no doubt. Over and over 
again I have seen, on preserving Gorgonids, numerous Amphipods 
(and other small Crustaceans) falling off the coral, when it was 
put into the preserving fluid, while it was hardly possible to dis- 
cover any of them on the living coral. But it would need a spe- 
cial study to find out about these small animals, for which I had 
no time, although I perfectly realized that here was a matter well 
worth a careful study. 
The Isopods appear to be less rich in cases of protective re- 
remblance. The best known case is Idothea marina and related 
species which bear a striking resemblance to the plants (especially 
Zostera-leaves) on which they are found. Another, still finer ex- 
ample I observed in Australia, an Isopod living on an Ascophyllum- 
like alga on the shores of N.S. Wales. Its colour is exactly that 
of the alga, greenish brown, and in shape it resembles the leaves 
of the alga, to which it clings very tenaciously, being also very 
flattened. It is exceedingly well concealed by this protective re- 
semblance — but, of course, this case comes under the head of 
adaptation to life on or among algæ, which it is not my intention to 
treat more specially in this paper. 
Upon the whole the Crustaceans appear to be a very promis- 
ing field for the study of protective adaptation; hardly any other 
group of marine animals will afford so many objects for the study 
of these phenomena. 
