CONCEALMENT AND COLORS IN CRUSTACEA—MINKIEWICZ. 473 
I have been able to show this more than once at the laboratory of 
Roscoff. On the other hand, the crab often takes bits of paper with 
its claws and throws them far away, as it rejects the nourishment 
that it can also hook anywhere on its carapace. 
There is nothing strange in this variability of the reactions, when 
analogous facts, sometimes much more striking among animals not 
operated upon, are borne in mind. The explanation is found in the 
internal perturbations of the physiological state, which are com- 
pletely unknown, but of which the modified reactions of the animals 
give incontestable proof. 
The essential thing in these experiments is that the instinctive 
actions of concealment take place after the removal of the brain. 
What conclusions can be drawn in regard to the psychology of 
instinct? I know of only two: Either it must be frankly admitted 
that we can know nothing definite, and, consequently, must re- 
nounce in scientific studies of instinct all psychological tendency, or 
else it must be declared as frankly that the animal psychism, at 
least the inferior, instinctive, and unconscious psychism, as it is 
customary to call it, is not necessarily connected with the brain; that 
it is, instead, diffused in the entire ganglionic nervous system with- 
out the necessity of its anatomical functional integrity. 
I might be criticized* on the ground that, in cutting the con- 
nectives, I did not eliminate other possible means of communication, 
as by the peripheral nervous network (cf. of the tegumentary nerve). 
But the experiments made afterwards at Villefranche-sur-Mer (1907) 
on completely decapitated Phronimas as well as the numerous 
analogous observations on completely decapitated insects and myria- 
pods, especially those of Wagner,’ on Blatta, Nepa cinerea, Geophilus 
longicornis, etc., show in an indisputable manner the slight founda- 
tion for this supposition. 
Thus, the experimental method by operation enables us to establish 
the physiological determinism of the instinct of self-concealment, 
which is nothing else than a series of refiex actions of the anterior 
thoracic extremities, induced by the tangoperceptions of the claws, 
directed by the tango- and chemoperceptions of the buccal pieces and 
helped on by the tangoperceptions of the flexible dorsal hooks. 
It is not difficult to demonstrate directly the sensibility, or per- 
haps the tactile receptibility, of the hooks. It would be most inter- 
esting to study their innervation in more detail. 
The determination here indicated is not yet complete, as it con- 
cerns only instinct artificially simplified in animals modified by the 
Ag, by M. Yves Delage in the discussion which took place after my first 
lecture at Roscoff (September 11, 1906). 
b’W. Wagner: Les problémes de la Zoopsychologie (St. Petersburg, in Rus- 
sian, 1896). 
