36 ZOOPHYTES. 



A portion E, being the lower part of D, was severed from it on the 

 17th of March following. The summit of this portion E, though afford- 

 ing symptoms of reproduction, generated no symmetrical head, until one 

 with 21 tentacula appeared on the 12th of October, and decayed in three 

 days. — PI. IV. fig. 2. Another head, being the third, quite symmetrical, 

 vigorous, and florid, with the same number of tentacula, succeeded it. 

 But the fourth was slightly distorted. A fifth was generated on the 8th 

 of December, and subsisted until the 17th. — PI. IV. fig. 4. 



Symptoms of internal decay at this time interrupting reproduction, it 

 was seen as represented, fig. 4. 



About 18 lines, F, were severed from the lower part of E, and con- 

 signed to a narrow glass cylinder, on January 4. after the preceding De- 

 cember. On February 11. a vigorous hydra, with 19 tentacula, had de- 

 veloped, and was then some days old. But, cramped for room, it had 

 turned upwards, as the section itself lay horizontally, fig. 5. Having sub- 

 sisted above a fortnight, it was succeeded by another with an equal num- 

 ber of tentacula, which burst on March 6. and fell in three days. The 

 section being now suspended in a more capacious vessel, its increment un- 

 restrained, made rapid advances with a third hydra, which subsisted four- 

 teen days from April 12. At this time the length of the new shoot 

 equalled the length. of the original section, and it had become nearly ver- 

 tical.— PL IV. fig. 6. 



Supervening transparence in June rendered farther observations un- 

 necessary. The total hydrse regenerated by this stalk and its sections in 

 506 days amounted to twelve in number. 



The following conclusions may be deduced from the preceding nar- 

 rative : — 



I. — ^The Tuhularia Indivisa consists of a single living hydra, sustained 

 on a fistulous stem, rooted irreversibly to a solid foundation. 



II. — The stem is occupied by a tenacious matter or pith, essential to 

 the permanent life and the animal functions of the product. 



III. — An external ovarium, composed of several clusters, is borne by 

 the hydra, each cluster consisting of several cysts, and each cyst contain- 

 ing an ovum or embryo. 



