220 ZOOPHYTES. 



In this manner five hydrae were generated on the main stem between 

 May 2 and 6, and seven on the branch between May 2 and 7. But the 

 branch becoming limber, proved in total decay on May 29. 



After the stem had been sundered near the root, a shoot rose from 

 the remaining stump, which bore a hydra in eight days. 



A twig from the sundered portion having come in contact with the 

 glass vessel containing it, extended and generated subordinate parts. 

 Thirteen hydrae were generated from them in eighteen days, and one ad- 

 ditional in the course of a month. The period of their subsistence was 

 usually two or three days. 



Three shoots had descended from the extremity of another sundered 

 stem, each extending half an inch in nine days, and then bearing a hydra. 

 Their length having doubled in a week, one bore two, and each of the 

 others three hydrae, all vigorous. 



Thus there are generations both by ascent and by descent, because a 

 prolific shoot rose from the preceding stump ; and prolific shoots descended 

 from the lower end of the section. 



These facts may be compared with what is said of the Sertularia 

 fascis, and of others. 



Considering the position allotted to this product by modern systema- 

 tists, the mode of its propagation merits notice. 



It is seen that the preceding species of the Campanularia or Sertularia, 

 the dichotoma, discharges a number of minute Medusae. The present species 

 bears a prolific ovoidal vesicle, exactly resembling a Florence oil flask, 

 with a long tubular neck and circular orifice. Vesicles of this kind, in- 

 terspersed irregularly with the twigs on the stem, have occurred in May 

 and in July. — Fig. 3. Instead of Medusae, they contain three or four 

 planulae, which are very conspicuous within ; figs. 4, 5, and escape when 

 mature, as white, fleshy, and a little flattened, fig. 6. 



The rarity of the product has opposed my further investigation of the 

 history of these creatures. If they truly belong to the same genus as the 

 Sertularia dichotoma, it would be strange to find one of them propagating 

 through the medium of a Medusa, and the other through that of a planula. 



Specimens of the Verticillata appear of finest quality in their earliest 



