284 A.J. Carlson. 



the body around as if to bite, reactions identically the same as 

 those of the intact animal. When these centipedes are cut in two 

 in the middle the posterior half exhibits the reactions just de- 

 scribed, with the exception that it does not turn over on its ventral 

 side so readily when placed on its baclc, but it attempts to do so 

 in every case. The number of segments may be further reduced 

 without destroying the coordinating mechanism of locomotion. If 

 the sections are made with a razor or a pair of sharp scissors, 

 the whole body may be divided Into portions of three or four seg- 

 ments in length, each portion still retaining coordination to the 

 extent that it walks across the t^ble and keeps up locomotion for 

 three to four minutes, but it exhibits no sense of equilibrium — 

 that Is, attempting to turn over on Its ventral side when placed on 

 Its back. The direction of the locomotion In these small portions 

 of the body Is almost invariably forwards. The beheaded Scolo- 

 pendra or Scolopocryptops live and react In this manner for three 

 to four days. After the initial restlessness, evidently due to the 

 stimulation from the lesion, it scarcely stirs If left undisturbed, al- 

 though its excitability Is retained apparently unimpaired for 24 

 to 48 hours. It does not react to light. When placed in a glass 

 jar provided with sand or moist earth in one corner It usually 

 comes to rest on these places rather than on the glass. 



The beheaded Hiinantariiim lives and reacts for seven to eight 

 days, showing much more "spontaneous" activity than the decapi- 

 tated Scolopendra. An 8 to 10 mm. long portion of the body 

 usually exhibits the same reflexes and degree of coordination as 

 the Scolopendra deprived of only Its head segment. A portion 

 of that length walks forwards or backwards with apparently per- 

 fect coordination of its legs, and it turns over on Its ventral side 

 when placed on Its back, keeping up these reactions for 24 to 48 

 hours after being isolated from the rest of the body. A portion 

 of three segments walks in either direction, the usual tendency 

 being to forward progression. A portion of five to six segments 

 exhibits the equilibrium reflex in attempting to regain its natural 

 position when placed on Its back. Longer portions turn over 

 promptly. 



