TUBULARIA. 45 



it was regenerated on the 28th, and decayed on the 30th, but still a new 

 hydra, on June 8th, replaced it, which fell on the 10th. Thus six hydrte 

 regenerated from the same stalk in 51 or 52 days. 



The hydra, fig. 2, h, was displayed April 14. It had fallen May 7, 

 and was regenerated on the 12th. But no reproduction followed this suc- 

 cessor. 



The hydra, fig. 2, c, was also displayed on 14th April, and fell on the 

 20th, without farther reproduction. Therefore, the former, b, regenerated 

 only two heads, and the latter but one. 



Although the whole stalks of this specimen, fig. 2, were prolific, it 

 never bore above eight hydrae at once, subsequent to the commencement of 

 their fall. 



On May 2. all the stalks were vacant : in five days the specimen had 

 seven heads. 



The specimen fig. 3, was totally vacant on May 2 ; and after various 

 reproductions, it was totally vacant again on May 14. The number of co- 

 temporary hydriB after they began to fall never exceeded three. The 

 hydra c, of this specimen, flourishing April 19. fell and was regenerated 

 for the fifth time, including preceding regenerations, on May 31 ; that is, 

 in 42 days. Progressive reduction of the number of reproduced organs is 

 proportional to the frequency of regeneration here, as in the Tubularla 

 iiidivisa. 



The hydra c had 14 tentacula on the third regeneration ; on the fifth 

 it had only 12. 



The same peculiarity has been evinced still more conspicuously in 

 other examples. Thus, the hydra fig. 2, ?, falling April 20, was replaced 

 on the 23d, by a fine head with 16 tentacula. This falling on the 28th, 

 was succeeded by one with 12 tentacula, on May 3. The latter had 

 fallen on the 9th of May, and it was renewed with 10 tentacula on the 

 12th. Having fallen, it was regenerated with 9 tentacula on the 28th. 

 This having fallen, a new hydra appeared next day, June 4. with only 

 seven ; which, on its fall, was replaced by yet another hydra, with no more 

 than six tentacula. The successive heads actually seen and enumerated 

 amounted to seven, all being in existence and inheriting the. summit of a 



