82 
not known, whether Nemerteans are unpalatable or otherwise their 
proboscis is a sufficiently protective weapon. Perhaps also this color- 
ation of the Synaptid has no such meaning at all. — An undoubted 
case of protective coloration is afforded by the small Synaptid, 
Synaptula hydriforme Lesueur from the West Indies, which is 
greenish, striped, so as to be almost indistinguishable among the 
ålgæ, where it lives. 
Among the Ophiurids some species of Ophiothela appear to 
be protectively coloured. They generally live upon Gorgonids, where 
their splendid coloration makes them fairly difficult to distinguish. 
Also young Astrophytids with their branching arms are often very 
hard to distinguish on branching Gorgonids. The same holds good 
of Astroceras pergamena Lym. 
In the Bay of Panama I observed a white Astrotoma (?) Y) on 
a white unbranched Gorgonian (Leptogorgia?). It seemed to be a 
very fine protective coloration; but afterwards the same species 
was found on a dark red Gorgonian, where it was exceedingly con- 
spicuous on account of its white colour. This case is, anyhow, 
very interesting in comparison with the Gastropod Ovulum living 
on the same Gorgonians. The latter carefully avoids Gorgonians 
differently coloured from itself or else perhaps adopts the colour 
of its host. The Ophiurid, having no eyes, cannot distingish the 
colour varieties of the Gorganians it lives on, and thus must make 
mistakes. At least so it would appear. 
VII: Coelenterates: 
Well protected as they are by their nematocysts the Coelente- 
rates would appear to need no protective coloration or resem- 
blance. Warning coloration would seem to be more useful and very 
probably the gorgeous colours of so many sea-anemones are warn- 
ing colours (Poulton, p. 166). ”) 
") I have as yet failed to find the specimens preserved, so I cannot give 
the name with certainty; but it appeared to be something like an Astro- 
toma. 
”) The gorgeous colours of so many forms of reef corals probably have 
nothing with warning or otherwise protective coloration to do. Partly, at 
least, they are due to symbiotic algæ (Zoochlorella) that live in the soft 
parts of the corals. 
