FRANDSEN. — REACTIONS OF UMAX MAXIMUS. 225 



give any characteristic paths. Two of the three moved only a short dis- 

 tance in wavy lines without recrossing their paths, and were in poor condi- 

 tion, for they did not go far, and shortly died. One extremely active little 

 individual moved ahead in a straight line quite across the floor, a distance 

 of eight or ten feet. With these few exceptions, it will be seen that 

 there is a very marked tendency to travel in loops. In general, the 

 loops varied in size from a couple of inches in diameter to two feet and 

 sometimes more. The animal generally makes a circle soon after starting 

 out, and then may travel for some distance before again recrossing its 

 tracks. The individuals which did the most looping also showed a 

 tendency, by gradually swinging away from the starting point, to make 

 larger and larger circles. Nos. 7, 8, 11, 13, 14, 16, 17, 19, and 22 all 

 showed this tendency. The smaller individuals usually make the 

 smaller loops, but this is not always the case. Although the paths made 

 by different animals have a very different appearance, they all show the 

 same general looping tendency. It will at once be noticed that all curves 

 are not in the same direction. Some are right-handed loops, others are 

 left-handed, and two cases, Nos. 10 and 12, contain loops of both right and 

 left hand character, or at least indicate a tendency to the formation of 

 such loops. As a rule, however, the individual shows a marked con- 

 stancy in the character of the loops made. Disregarding the two cases 

 in which there were both right and left hand loops, we have ten individuals 

 with a tendency to circle to the right and eight individuals with just as 

 marked a tendency to circle to the left. This does not indicate a very 

 great preponderance of individuals travelling to the right. If the total 

 space travelled over by all individuals be considered, I think it might 

 show, on the average, a more marked swerving to the right than does a 

 counting of right and left circling individuals, but I have not measured 

 the distances carefully enough to speak confidently on this point. The 

 evidence thus far accumulated in regard to an asymmetrical response of 

 the right and left sides to artificial stimuli points to a greater sensitive- 

 ness of the left side, which is perhaps correlated with a slight average 

 tendency to move toward the right side more than to the left. 



Summary of Part III. 



These studies on the light responses of Limax maximus seem to estab- 

 lish the following points: — 



(1) The animals are markedly phototactic. 



(2) There are individual differences in phototaxis, as there are in 

 geotaxis. 



vol. xxxvn. — 15 



