THE NERVE-NET 125 



held under careful observation. These contracted at the 

 level at which they had been cut so as to look like an ac- 

 tinian normally withdrawn!. They soon filled themselves 

 with water and, in twelve to fifteen hours after the oper- 

 ation, many of them were creeping about precisely as the 

 whole animal did. A single record will illustrate this 

 condition. One of the animals without its oral disc began 

 creeping and was observed to carry out 4 movements in 

 16.5 minutes, travelling in that period a distance of 7 

 millimeters. An animal with its oral disc intact that had 

 been kept under similar conditions as a control, carried 

 out 4 locomotor movements in 22.5 minutes, travelling in 

 that period 6 millimeters. As the differences between 

 these two sets of records are no more than may be seen in 

 any pair of normal individuals, the locomotion of the two 

 animals may be regarded as essentially identical. Individ- 

 uals without oral discs not only creep as whole individuals 

 do, but they also attach themselves to a glass surface as 

 firmly as do those with oral discs. Furthermore, those 

 without oral discs creep away from the light as consist- 

 ently as do normal individuals. In fact, so far as the 

 creeping is concerned, it is impossible to distinguish one 

 class from the other, except perhaps that the operated 

 animals are somewhat less inclined to creep than the 

 normal ones are. 



These results are in entire accord with Loeb 's investi- 

 gations (1895, 1899) in which he has shown that an Ac- 

 tinia equina from which the oral end has been cut off, 

 will creep more or less continuously on glass, and will 

 attach itself firmly to a mussel shell just as a normal ani- 

 mal will. They are also in accord with Jordan's results 

 (1908), in which it was shown that the reflex excitability 

 and muscle tonus of actinians is not under the control 

 of superior nervous centers lodged, for instance, in the 



