512 'Journal of Comparative Neurology and Psychology. 



general fsychologique for the establishment of a Section d' etude de dressage sctentt- 

 fique, the actual formation of which, however, appears to have been postponed. 



We shall now take up in order the titles in our bibliography, referring to them 

 by number, and try to indicate the important points brought out in each paper. 



I. Of this article by Bohn, the substance is as follows: Those animals which 

 show most rapid transmission of nervous impulse from one segment to others 

 would seem to have most psychic individuality, but this is a vague and obscure 

 concept. The degree of coordination depends on the development of the receptive 

 sensory apparatus. 



2 and 3. Acanthia lectularia is a negatively phototropic insect. Bohn shows 

 that when it undergoes a change of illumination, its tendency is to rotate through 

 180° in a direction which is constant during the day, and changes towards evening. 

 This reaction is but poorly adaptive, since under certain conditions it may lead 

 the animal to turn toward the light. For instance, if the insect is moving along 

 a shadow directly away from the light, and comes to the end of the shadow, 

 it will turn through 180° and thus be brought to face the light. Again, it may either 

 approach or move away from a dark screen, as a consequence of its turning always 

 in the same direction at a given time of the day. The mollusc Littorina, on the 

 other hand, is always, at a given hour, attracted by a dark screen. The superior 

 adaptiveness of Littorina's behavior may be due to the fact that in nature it is 

 accustomed to seek shade, while Acanthia does not come out on bright surfaces 

 at all during the day. 



4 and 5. The results stated in these papers were published later in 27. 



6. The results of this paper are stated in paper number 15. 



7. As between the "teleological" interpretations of Jennings and the mechanical 

 explanations of Loeb, Bohn would insist on taking account of the past experience 

 of the animal in determining tropisms. 



8. This paper must be taken in connection with that by Pieron numbered 59 

 in the bibliography, and with the paper by Bohn and Pieron numbered 28. 

 Actinia equina closes when the sea withdraws, and opens when the sea returns. 

 Pieron found that the specimens he kept in the laboratory opened under the 

 following conditions: when sea-water was made to run over them, when the 

 water was agitated, when it was reoxygenated, when food substances were brought 

 near. They closed when they had been some little time dry, when the water was 

 deoxygenated, when they received mechanical shocks, and after grave lesion by 

 toxic substances. In the pools from which they were taken, they expand at the 

 mechanical agitation caused by the first wave of the rising tide that reaches the 

 pool. They close, at falling tide, before the pool is stagnant. They thus show 

 "anticipation," in closing before there is actual need of it. Pieron did not find, 

 however, that rhythmic opening and closing in accord with the tides persisted in 

 the laboratory (59). Bohn and Pieron, in their joint paper (28), explain the 

 difference between their results in regard to this last point, — Bohn having found 

 a persistence of the tidal rhythm in the laboratory with Actinia equina as with 

 Convoluta roscoffensis, — by the difference in habitat between their specimens. 

 Bohn's were taken from high on the side of a vertical wall, where the contrast be- 

 tween the conditions at high tide and those at low tide was very marked. Pieron's 

 were taken from pools not wholly dry even at low tide. The "anticipation" 

 noted by Pieron is a step towards the development of such a rhythm as that 



