TUBULARIA. 25 



It does not appear that the embryo ultimately constituting a new 

 bead displaces its precursor, that its rise and developement are so imme- 

 mediate as to bring the two in contact. 



The distortion and monstrosity consequent on wounds indicate that 

 the injury is received while the embryo is below ; but the variable and ir- 

 regular evolution of the parts embarrass our investigation of the original 

 site of the germinating principle. 



In a comparative experiment to ascertain the concomitants of post- 

 poned evolution, two congeries of intertwisted stalks were cut over. 

 The one was founded on a stone, the other on a shell. More vigorous 

 reproduction ensued from the latter, where the section had been twenty- 

 one lines above the root, than with the former, where within six lines 

 of it. Conical projections arose from all the stumps, and in thirteen days 

 a minute head sprouted from one of each congeries. Eight sprung and 

 flourished ultimately from that on the shell, but the last not until 63 days 

 after the first, by which time, the stump advancing fastest had regenerated 

 three heads, and was reddening again — the wonted prognostic of subse- 

 quent evolution. This congeries is represented as appearing 20 days after 

 the date of the sections, PI. II. fig. 6, and 67 days later than this figure, 

 by fig. 10. Its intermediate stages are seen in figs. 7, 8, 9.* The heads 

 had 12 or 14 tentacula ; they were generally of short duration, the stalks 

 frequently abortive ; and in about three months from the date of the ex- 

 periment they ceased to flourish, though again reddening. In eight months 

 observation was finally abandoned. I now speak of the group upon the 

 shell remaining after separation of the upper portion of the congeries. 



The sundered or upper portion of this same group was found flourish- 

 ing sixteen days after separation. 



As to the congeries on the stone, which consisted of four stalks, after 

 four vigorous new heads had been generated for the second time, the group 

 was cut over again three lines lower than the previous section, when, in 



* Date of fig. 6, December 22. 1824 ; of figs. 7, 8, 9, January 17, 18, 19, 1825 ; of 

 fig. 10, February 27. 182.5. Tliis last view is from the side opposite to the view of the 

 jjreceding figures. 



VOL. I. D 



