SERTULAEIA. 189 



An evident tendency to the nature and form of vegetable growth, 

 appears in the vertical direction of the regenerations. Shoots double the 

 length of the shortest section above mentioned, rose perpendicularly from 

 both ends, as it lay horizontally. 



Long ovate vesicles, with a transparent integument, have occurred on 

 this product in May. I could not observe that they occupied a peculiar 

 place. Each contained from four to six corpuscula, chiefly spherical, or 

 tending to this form, and arranged in a curve. They are very seldom 

 found, and an intervq,! of eight years having interrupted the prosecution of 

 earlier observations, circumstances intervened, on their renewal, which 

 prevented me from bringing them to a successful conclusion. — Fig. 11. 



Plate XXXVI. 



Fig. 1. Sertularia ( Plumularia) fascis. 



2. Section, comprehending the extremity of a specimen which shows 



the arrangement of the parts ; the cells and hydrse. 



3. Hydra. 



4. Hydra. 



5. Section of a stem generating shoots by descent. 



6. Section of a stem generating shoots by ascent. 



7. The same, farther advanced. The evolution of a hydra, a, followed 



in eight days after the section was made. 



8. The same, farther advanced, by the evolution of a second hydra, b. 



9. The same, still farther advanced, as seen ten days subsequent to the 



section. 



10. The same, with generations, as viewed by a lens, twelve days after 



the section. This is in a horizontal position, the shoots from each 

 end are vertical. The preceding figures, on a larger scale, represent 

 the section in a vertical position. 



11. Section bearing vesicles. Hydra unfolding, a. 



All the preceding, except fig. 1, enlarged. 



^ 11. Sertularia argentea — Squirrets Tail. — Plates XXXVII. 

 XXXVIII. — A complete dissertation on the tribe of Sertularise, should 

 comprehend many other facts and subjects besides those to be found in 



