HYDRA. 99 



9. The same enlarged as on May 25. — The formation altered. 



10. The same as appearing June 21. — The prominences elon- 



gated. 



11. The same approaching symmetry. — June 26. 



12. The same become more symmetrical. — Augmt 9. 



13. The same upper portion, or fig. 7, quite symmetrical as 



seen August 21. 



14. The same with its progeny. — September 29. 



15. The specimen, fig. 3, b, viewed separately on selection for 



experiment. — March 12. 



16. Stump of fig. 15, after bisection of the entire animal. — 



March 12. 



17. The same stump having regenerated the upper portion with 



tentacula. — March 29. 



18. Upper portion severed on March 12 from fig. 15 (originally 



fig. 3, b), as seen on March 29. 



19. The same enlarged. 



20. The same, the tentacula being obliterated, enlarged. — 



June 21. 



21. The same, with irregular regenerating tentacula. — July 23. 



22. The same, having attained symmetry. — August 9. 



23. The same having generated progeny. — August 21. 



24. The same with additional progeny. — September 29. 



25. White fleshy corpusculum in motion. — 3Iay 25. 



26. Hydra relaxing from its usual form. 



§ 2. Origin of the Hi/dra tuba. — Plates XV. XVI. XVII. 



Hitherto we have considered the hydra as a perfect and independent 

 animal, living for itself, and carrying on a race of beings, its posterity, in 

 its own likeness. But we have still to penetrate farther into its nature. 

 No doubt, some of the principal purposes of physiology are already ful- 

 filled, and the reader will not find it difficult to understand from the pre- 

 ceding detail, the precise mode whereby such accessions are gained by 

 Zoophytes as to render these productions of admirable luxuriance and 

 beauty. It will be seen how they may originate from a single individual, 



