Physiology of Ventral J\ crze Cord of Myriapoda. 287 



When the milllped': Jules is cut transversely in the middle the 

 coordination is destroyed in the posterior half. The anterior 

 portion continues to move about for a short time but loss of co- 

 ordination and death ensue within 10 to 20 min., and the same is 

 true when the animal is decapitated. This animal is therefore 

 not suited for the study of the reflexes and the relative indepen- 

 dence of the coordinating mechanisms of the segmental ganglia. 



To recapitulate : Locoitiotion, movements to regain normal 

 posture, as well as all contact reactions in the centipedes are ob- 

 viously reflex movements not dependent on the cesophageal nerv- 

 ous complex or "brain," as the decapitated centipede exhibits the 

 same reactions and movements as the intact animal, save that it 

 does not avoid light and cannot feed or make passages for itself 

 in the ground. The decapitated centipede is not abnormally rest- 

 less, so that any inhibitory functions can be ascribed to the cesoph- 

 ageal nervous complex, nor is it quiescent to the extent that so- 

 called "spontaneous" movements may be said to be wanting. The 

 bending of the anterior part of the body preparatory to bite the 

 object touching the posterior part is a reflex not dependent on the 

 "brain." The maintenance of the body ventral side down is also 

 a reflex through the segmental ganglia, the turning of the body 

 to the ventral side when placed on its back probably d^iyending 

 not so much on the touch impressions on the dorsal side as the 

 absence of the normal touch impressions from the contact of the 

 legs with the ground. The relatively great segmental indepen- 

 dence of this equilibrium reflex and especially of the reflex and co- 

 ordinating mechanisjtis of locomotion is shown by the fact that 

 these are exhibited by any portion of the body measuring not less 

 than three intact segments in length. 



The short and stout centipedes {Scolopendra, Scolopocryptops) 

 exhibit a greater antero-posterior differentiation and a less degree 

 of segmental independence than do the long and slender centi- 

 pedes {Himantarium, Stylolaemus) . These latter centipedes re- 

 tain the annelid mode of locomotion , and the transmission of the 

 nervous impulse through their ventral nerve-cord is slower. 



