Soine Phenoinona uf Regeneration in Lininodrilus und related Fornis. 419 



line between lateral proliferatioiis from the ectoderin he thought they 

 formed an axis about wliich otlier struetures arise much as they do 

 about the notochord in vertebrates and therefore he termed them 

 »Chordazellen«. BuLow (83) nierely mentions similar cells as being 

 present in Liimbriculus. Later Randolph (92) in an aecount of the 

 posterior regeneration in Lmnbriculus described them and applied 

 the now generally accepted term neoblast. She found that they migrated 

 from the uninjured parts of the body to the wound and she derived 

 from them the walls of the coelomic sacks, the longitudinal muscles, 

 the ventral blood vessels and the ventral mesentery. She suggests that 

 "they may represent the ova of the primitive worm which were origi- 

 nally prodiiced in every somite". Haase found them at the posterior end 

 in Tubifex but as he did not study the mesoderm he expresses no opinion 

 regarding its derivation from the neoblasts, merely stating that they 

 take no part in the formation of the entoderm or the nerve. Iwanow (03) 

 has followed Randolph and says that in Lumbriculus »die Neoblasten 

 dem größten Teil aller mesodermalen Gebilde der Rumpfsegmente 

 den Ursprung geben«. Iwanow admits seeing the enlarged ectodermal 

 cells which other authors describe as entering the coelom and forming 

 the mesoderm but he denies that they break through the basement 

 membrane. According to him they remain in the ectoderm, subse- 

 quently become smaller by division and form the ventral nerve cord, 

 Hepke (97) is entirely opposed to the view held by these workers and 

 expresses himself in the foUowing words »Was nun Randolph hin- 

 sichtlich der Bedeutung ihrer Neoblasten, also der ,Chordazellen' 

 Semper's angibt, nämlich daß sie dazu da seien, um möghchst schnell 

 wieder neues Mesodermgewebe zu bilden, sobald durch irgend einen 

 Umstand dazu Veranlassung gegeben ist, hat sich bei meinen Regene- 

 rationsversuchen an den Naiden nicht bestätigt; denn ich hatte hier 

 nie Gelegenheit zu konstatieren, daß von der Gruppe der Neoblasten 

 aus sich jemals Zellen abzweigten oder zu Bildung von Mesoderm- 

 gewebe beitrugen, und obwohl mitunter eine Teilung derselben statt- 

 fand, so behielten die daraus entstandenden Produkte ihren Platz 

 doch beständig bei.« von Wagner (OG) is the last worker to consider 

 the neoblasts but he comes to no definite conclusion regarding their 

 function. However he believes them to be of "reparative Nature" 

 although he thinks that too much has been ascribed to them. At one 

 point he expresses this opinion regarding their relation to the ectoderm; 

 »Unter allen Umständen muß ich der von Randolph (und Janda) 

 gegebenen Darstellung gegenüber das Recht der Epidermis wahren, 



