7. Restitutionslehre. 245 



7. Restitutionslehre. 



(Siehe auch Nr. 607, 635, 652.) 



678) Steininann, P. (Basel), Regeneration und Selektion. 



(Verh. Schweiz, nat. Ges. Vers. 93,1. p. 294—295. 1910.) 

 Unterscheidung zwischen primitivem (nicht lokalisiertem) und adaptivem 

 (örtlich beschränktem) Regenerationsvermögen. M. Daiber (Zürich). 



679) Müller, K. (Zool. Inst. Marburg), Versuche über die Regene- 

 rationsfähigkeit der Süßwasserschwämme. 



(Zoolog. Anzeiger 37,3/4. p. 83—88. 1911.) 

 Vollkommen dissoziierte Zellelemente unserer einheimischen Süßwasser- 

 schwämme (Spongilla lacustris) und Ephydatia Mülleri), die der Verf. 

 z. B. durch Hindurchpressen des Materials kleiner Schwammstückchen durch 

 feine Gaze erhielt, sind imstande, zu Zellkomplexen zu verschmelzen, die sich 

 festsetzen und zu normalen, lebenskräftigen Schwämmchen auswachsen. Hier- 

 bei wird das gesamte Skelett, das Geißelkammer- und Kanalsystem neu ge- 

 bildet. F. Pax (Breslau). 



680) Jorrey, H. B. (Univ. of California), Biological Studies on Cory- 

 morpha III. — Regeneration of Hydranth and Holdfast. Note on 

 Geotropism in Corymorpha. Contributions from the Laboratory of the 

 Marine Biological Association of San Diego. 



(Univ. of California Publications in Zoölogy 6,10/11. p. 205—224. 1910.) 

 Regeneration in pieces of the column of the adult Corymorpha palma does 

 not follow strietly embryonic lines of development, but is modified by 

 the differentiation of the piece. The wound closes by shrinkage of the axial 

 endoderm and by the activity of the circular muscles. The new hydranth 

 cavity is formed by degeneration of the axial endoderm cells and gradual 

 disappearance of the canals. The proximal tentacles appear in two sets, the 

 first set one to a canal, the second set one by one between and on the same 

 level. The distal tentacles develop in successive groups, often in quartettes 

 as in the embryo. The axis of the larval tentacle is formed by the extension 

 of a Single row of cells from the simple endoderm, that of the regenerating 

 adult by the outpushing of a mass of cells from the more complex endoderm. 

 The regeneration of the peduncles is essentially the same as in embryonic de- 

 velopment, involving a distinct evagination. Of the cut is made through the 

 region covered by perisarc, new perisarc is formed within the old at a certain 

 proportional distance from the proximal tentacles of the new hydranth a cut 

 through the frustular zone, accelerates the development of the frustules distal to 

 the wound, by removing the more proximal functional hold fasts. A series of 

 experiments showed that both distal and proximal regeneration in a larva is 

 essentially identical with embryonic development of hydranth and frustules. 

 Larval tissues produce larval stuctures in the embryonic way; while adult tis- 

 sues, more highly differentiated and complex, regenerate adult structures by 

 a similar but somewhat more complicated process, due to the physiological 

 condition present in the regenerating piece and governing the process of re- 

 generation. 



Though the larva of Corymorpha palma exhibits marked negative geo- 

 tropism in locomotion, a series of experiments indicates that gravity plays no 

 part in Controlling the point of emergence of the embryo from the egg-case r 

 and its first locomotor movements. The frustules, however, although their 



