xm 



REMARKS OX REGENERATION ' 



I. ON THE REGENERATION OF THE BODY IN PANTOPODS 



1. So FAR as I know, it is generally held that in Arthro- 

 pods regeneration is possible only in the appendages, while 

 segments of the trunk are not regenerated. According to 

 experiments which I made at Woods Hole last year, Panto- 

 pods, or at least one form of this group, Phoxichilidium 

 maxillara, form an exception to this rule. 



The trunk of Phoxichilidium maxillara (Fig. 95) is about 

 1cm. long. The animal remains alive for weeks in a dish of 

 sea-water. It is, like most of the free-moving inhabitants 

 of the surface of the sea, positively heliotropic. 2 If the 

 body of one of these animals is cut in two by a transverse 

 incision (at a, Fig. 95), each of the pieces is still capable of 

 locomotion. If the pieces are exposed to the light, it is 

 found that the oral piece continues to be heliotropic, while 

 the aboral piece moves about independently of the light. 

 The latter do not show much tendency to progressive 

 motion. 



That injured Pantopods can remain alive has already 

 been observed by Dohrn. The latter writes : 



I have observed that individuals continued to live for days 

 even when all-of the extremities have been cut off. I have even 

 cut a female specimen of Barana castelli in two, dissected the 

 anterior portion of the body, and kept the posterior portion, carry- 

 ing the extremities V to VII, alive for fully four weeks. 3 



1 ArchivfUr Entwickelungsmechanik der Orgamsmen, Vol. II (1895), p. 250. 



2 Part I, p. 1. 



3 A. DOHRX, Fauna und Flora des Golfes von Neapel; III, " Pantopoda " (Leip- 

 zig, 1881), p. 81. 



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