THE NEMATOCYSTS OF EOLIDS 
141 
and that in certain highly speciahzed Cnidaria, nematocysts sub- 
serving the secondary function have replaced the more primitive 
prehensile organs. As eolids feed on coelenterates provided with 
large numbers of prehensile nematoc^^sts, the observed inade- 
quacy of the protection afforded is neither more nor less than 
one might expect. 
On the basis of experiments similar to those I have presented 
in brief, Cuenot has concluded that the defensive value of eolidian 
nematocysts is slight. This inference, which the behavior of various 
fish makes valid receives additional support from the observations 
of Toppe and the conclusions to be drawn from them. It would 
be a mistake however to postulate complete inadequacy, for un- 
questionably the presence of nematocysts of all kinds in the cnido- 
phores gives the cerata certain gustatorial peculiarities, which 
otherwise they would lack. When crushed on the tip of the tongue 
the sensation produced by a ceras is not unlike that of Tabasco 
Sauce. If this is added to the peculiarity, whatever it be, that 
renders nudibranchs in general distasteful to fish, we may conclude 
that a slight degree of defensive value attaches to the borrowed 
nettles. 
According to Garstang's view (^88), shared by Grosvenor, the 
bright colors of the cerata serve "to direct the experimental 
attacks of young and inexperienced enemies to the non-vital 
papillae, and away from the vital and inconspicuously colored 
parts of the body." The habit of responding to stimulation by 
erection, insures that the cerata shall bear the brunt of any attack 
whatever the experience of the enemy. As autotomy takes place 
with the greatest ease, it often happens during an encounter, that 
an eolid is obscured by a cloud of unattached brightly colored 
appendages, which, since their owner resembles the background, 
are certain to catch the eye of the enemy. Granted that the cerata 
are at least as distasteful as the body of the eolid ; that in addi- 
tion the presence of certain nematocysts adds even slightly to 
the disagreeable qualities, and one has in hand perhaps one of the 
minor factors in the persistance of the nematocyst-habit. 
