EXPERIMENTS ON WORMS 99 



and it is not possible for stimuli to be transmitted. 

 In the muscles of the blood-vessels of the Vertebrates, 

 however, a conduction of the stimulation from element 

 to element is possible. For this reason their reactions 

 remain intact even in higher animals after destruction 

 of the corresponding segments of the spinal cord. 

 In Nereis, after division of the ganglion-chain, a 

 phenomenon may be observed that reminds one of 

 the Brondgeestian phenomenon. The back part of 

 the body becomes more flat, while the part that is 

 connected with the brain remains round. This indi- 

 cates a relaxation of the ring-muscles in the part of 

 the animal that is situated behind the point of 

 division. 



The results of our physiological analysis of the 

 functions of the central nervous system in Annelids are 

 in perfect harmony with Professor C. O. Whitman's 

 investigations on the morphological structure of the 

 central nervous system in Annelids. He arrives at the 

 conclusion that the brain of Annelids is not of a higher 



O 



order than the other segmental ganglia (7). 



BIBLIOGRAPHY. 



1. LANG, A. Untersuchungen zur vergleichenden Anatomie und 

 Histologie des Nervensystems der Plathelminthen. Mittheil. aus der 

 Zoolog. Station zu Neap el, Bd. I. 



2. LOEB, J. Beitrdge zur Gehirnphysiologie der Wiirmer, 

 Pfluger's Archil*, Bd. 56, 1894 ; and Ueber kiinstlichc Umivand- 

 lung positiv helistropischer Thicre in negativ heliotropische und um- 

 gekehrt, P finger's Archiv, Bd. 54, 1893. 



3. GRABER. Grundlinien zur Erforschung des Helligkeits-und 



