SEETULAEIA. 183 



wise present. Eight days afterwards, the vessel being emptied and re- 

 plenished, hundreds of nascent Sertularise were found overspreading the 

 bottom, and many occupied the sides. 



The planulae often show a tendency to ascend, and the root detached 

 may be borne upwards, which will account for the heights of the nascent 

 products. Nor is the peculiar curve formed with the side of a vessel by 

 fluids to be overlooked. At the same time, as in the progeny of the Me- 

 dusae, there are some principles producing such effects not readily under- 

 stood. 



Considerable disparity appears in the form of the nascent Sertularine. 

 The root is of the same character as that of others. — Figs. 11, 12, 13, 14. 

 A spine rises from a circular spot as usual, fig. 15, budding first into one 

 cell, and then into a second, which is higher. — Fig. 16. The diffusing 

 parts of the root extend farther, and become fainter with the develope- 

 ment of the buds. — Figs. 17, 18. At an early stage the stem appears di- 

 vided by deep-marked, irregular articulations. — Figs. 19, 20. But it does 

 not appear that any strict uniformity prevails among the different young. 

 — Figs. 21, 22. Their advance is progressive, denoted by the number of 

 hydraj and buds. — Figs. 23, 24, 25, 26, 27. I have not been able to effect 

 their preservation until the evolution of more than five. 



From such early decay, it is impossible to discover how that modifi- 

 cation finally converting this Sertularia into its proper form ensues. The 

 disparities were so conspicuous, that, until numerous observations ascer- 

 tained the fact, I found it difficult to reconcile the production of the vari- 

 ous nascent products to a parent of the same species. 



The following general results were obtained : — 



I. The Sertularia (Plumularia) falcata is always of a honey-yellow 

 colour, or nearly so, if adult ; the reproductions are white. 



II. Numerous ovoidal vesicles are borne on the branches, during spring, 

 which, on different specimens, are either pure white or vivid yellow. 



III. The colour of the vesicle is derived from the contents, the side 

 being transparent ; but both kinds of vesicle are never found on the same 

 specimen. 



