4 George Thomas Hargitt 



contact : If the end of the piece was in contact with a sohd ob- 

 ject a stolon was formed; if the end was surrounded by water 

 a hydranth was formed. That contact has no efifect on the re- 

 generation in Tubularia crocca, T. tenella, and T. larynx is shown 

 by the following examples : In several experiments the pieces 

 were simply laid flat on the bottom of the dish. Regeneration 

 was as follows : In T. larynx hydranths almost always formed 

 at both ends ; stolons never formed. In T. crocca and T. tenella 

 hydranths developed at the distal end first and cjuite often at the 

 other end also ; stolons very rarely formed. In several pieces 

 oi T. crocca a stolon-like growth along the bottom of the dish 

 was the first indication of regeneration. This growth continued 

 for quite a distance and then turned upward away from the dish 

 and formed a hydranth. Experiments on Endendrinni and Pcn- 

 naria confirmed Loeb's results with Margelis and Pcnnaria, at 

 least to a great extent. Pieces of Pcnnaria, when laid flat on the 

 bottom of the dish, almost invariably formed stolons from the 

 ends of the stems which were in contact with the glass. It was 

 only from those branches which Avere completely surrounded by 

 water that hydranths developed. Tliis formation of stolons took 

 place as readily from the distal as from the proximal end In 

 one case regeneration in Fcnnuria was very similar to that in 

 Tubularia crocca, viz., the formation of a stolon-like growth 

 along the bottom of the dish and later the growth upward and 

 the formation of a hydranth (fig. 8). In general, Eudendriunt 

 showed the same phenomenon, though the influence of contact was 

 not so marked. Indeed, in one instance, the cut end of a branch 

 in direct contact with the glass formed a hydranth. When Tubu- 

 laria and Pcnnaria were placed in sand no stolons formed from 

 the end in the sand, though this may have been due to the lack 

 of oxygen, as Loeb (1892, p. (34) suggests. 



Driesch (1897), Peebles (1900), and others state that when 

 the end of Tubularia is cut obliquely the tentacle anlagcn will be 

 laid down obliquely. Peebles found this variable, however, and 

 in a later paper (1902) she obtained the following results: When 

 long and short pieces were grafted by oblique surfaces, the re- 

 sulting anlagen were sometimes obliquely and sometimes squarely 



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