TUBULARIA. 29 



a fifth bead, well defined, was visible within the stalk : the tentacula 

 were folded longitudinally together ; and the disc denoted by a convex 

 outline, all the parts being very conspicuous through the delicate inteon- 

 ment investing them. Next evening the head was displayed with 19 ten- 

 tacula. It became fine and vigorous ; none of equal dimensions had been 

 regenerated ; its shape was quite symmetrical, it rose perpendicularly, and 

 in every thing it proved perfect. The rudiments of an ovarium could be 

 recognised on the fifth day ; but on the seventh this promising reproduc- 

 tion separated from the stalk and fell. A very short interval then elapsed, 

 as on the following evening a new head was bursting from the stalk, which 

 became fine, and like the last, exhibited 19 tentacula. — PI. IV. fig. 9. 

 But it flourished only two or three days ; yet the reproductive energies 

 were not totally exhausted, for the vacant summit reddening again ex- 

 posed an embryo rising within, which was displayed as a head with 20 ten- 

 tacula on the 12th of December, and it subsisted ten days. This was the 

 last organization matured, for although the indications of an embryo ap- 

 peared a fortnight later, it proved abortive. On supervening transparence 

 the specimen was abandoned, after remaining the subject of observation 

 for fifteen months. 



It is to be deduced from the preceding experiment, — 1. In the course 

 of 395 days seven successive heads had been borne by the same specimen 

 of the tubularia, subsequent to its having attained a high stage of maturity. 

 2. The interval between the earlier reproductions infinitely exceeded the 

 ordinary natural period, which is about fourteen days. The first regene- 

 rated head required 60 days, the second 90 ; and 143 elapsed between the 

 second and the third. 3. But great irregularity followed, as the fourth 

 and fifth head required only 14 days each ; the sixth only 9, and the 

 seventh 31. 4. The first and second reproductions were distorted : the 

 fifth was perfect. 5. The tendency to symmetry was progressive, and at last 

 very nearly attained. 



The extraordinary intervals requisite for bringing the germ or embryo 

 to perfection cannot escape notice, no less than 60 days from the date of 

 the experiment being essential for maturity of the first reo-enerated head • 

 150 for that of the second, and 293 for that of the third. It is alike sin- 



