270 H. S. WILLIS. 



their locomotion from the source of stimulation, i. e., they orient 

 and are negative. Parts containing a nucleus respond in the 

 same manner; those without a nucleus, however, do not orient. 



3. The rate of locomotion varies greatly in different indi- 

 viduals. Large specimens move more rapidly than small speci- 

 mens, the rate of locomotion bearing a fairly definite ratio to the 

 size of the specimen. The rate of locomotion in nucleated seg- 

 ments bears essentially the same ratio to their size as it does in 

 normal individuals. Segments without a nucleus show very little 

 locomotion and this is always relatively very slow and irregular. 



4. The size of the parts, the contractile vacuole, and the 

 position which the parts occupied in the intact specimens before 

 division seem to be in no way responsible for differences in the 

 behavior of nucleated and enucleated parts of Amceba. 



5. The only other known respect aside from those mentioned 

 in which the two parts differ concerns the nucleus. Conse- 

 quently the differences in the behavior of these parts are, in all 

 probability, in some way related to the nucleus. 



6. The regulatory influence of the nucleus on behavior in 

 Amceba seems to be brought about by some sort of an influence 

 upon the attachment of the organism to the substratum. 



LITERATURE CITED. 

 Dellenger, O. P. 



'06 Locomotion of Amcebae and Allied Forms. Jour. Exp. Zool., Vol. 3, pp. 



337-358. 

 Gruber, K. 



'12 Biologische und experimentelle Untersuchungen an Amceba proteus. 



Arch. f. Protistenk., Bd. 25, S. 316-376. 

 Hofer, Bruno. 



'90 Einfluss des Kerns auf das Protoplasmas, Jena. Zeit. f. Nat., Bd. 2%, S. 



I05-I75- 

 Jennings, H. S. 



'04 Contributions to the Study of the Behavior of Lower Organisms. Carnegie 



Inst. of Washington, Pub. No. 16, 256 pp. 

 '06 Behavior of Lower Organisms. New York. 366 pp. 

 Mast, S. O. 



'n Light and the Behavior of Organisms. New York. 410 pp. 

 '10 Reactions in Amceba to Light. Jour. Exp. Zool., Vol. 9, pp. 265-277. 

 Stole, A. 



'10 Uber kernlose Individuen und kernlose Teile von Amceba proteus. Arch. 



f. Entom., Bd. 29, S. 152-168. 

 Verworn, Max. 



'09 Allgemeine Physiologic, 700 pp. 



