Regeneration in Hydroniedusae 29 



Fig. 3. Tuhnlaria crocca. Distal end showing the tentacle 

 anlagen. 



Fig. 4. Tubularia crocea grafted by proximal ends. 



Fig. 5. Tuhnlaria crocca, distal end in sand, new hydranth 

 having regenerated. The unshaded portion is the old stem. 



Fig. 6. Pcnnaria, distal end in sand showing regeneration. 

 Unshaded portion is the old stem. 



Fig. 7. Pcnnaria, stolon in sand showing regeneration. Un- 

 shaded portion is old stem. 



Fig. 8. Pcnnaria lying flat on the bottom of the dish, with re- 

 generating hydranth. Unshaded portion is old stem. 



Fig. 9. Pcnnaria and Endcndrinni grafted, st. — stolons from 

 Pcnnaria. 



Fig. 10. Pcnnaria showing holdfasts and hydranths. This 

 drawing is made from parts of two different stems. 



Figs. II, 12. Regenerated hydranths of Tuhnlaria larynx. 



Figs. 13a, 13&. Regenerating hydranths of Tuhnlaria larynx, 

 showing the tentacle anlagen. Developing gonads in black. 



Figs. 14a, 14&, 14c. Early stages in the development of the 

 hydranths of Tuhnlaria tcnclla. 



Figs. 14c?, 14^', 14/. Hydranths of Tuhnlaria tcnclla after emer- 

 gence from the perisarc. 



Fig. 15. Pcnnaria anchored to the bottom of the dish by the 

 distal end, showing regeneration. Unshaded portion is old stem. 



Figs. 16-24. Tuhnlaria crocca. 



Fig. 16. Early stages in the folding of the ectoderm and ento- 

 derm to form the proximal tentacle. X6oo. 



Figs. 17, 18. Later stages of folding. X6oo. 



Figs. 19, 20. Ectoderm folding around the entoderm to cut ofif 

 the proximal tentacle. X500. 



Fig. 21. Promixal tentacles separated from the hydranth body. 



X500- 



Figs. 22, 23. Two stages in the development of the distal ten- 

 tacles. Column of entoderm cells being formed. Ectoderm 

 folds around this column to cut off the tentacle. X6oo. 



Fig. 24. Separation of a mass of entoderm cells in a column. 



303 



