208 ZOOPHYTES. 



PI. XXXVIII. fig. 16. Third, Long flask-shape or ampullate vesicles 

 sustained on the twigs issuing from the branches, which vesicles were not 

 half as large as the horns. Yellow planulse, half a line long, were pro- 

 duced from these cornute vesicles, exhibiting nothing remarkable. — 

 Figs. 16, 17. They proved rather languid, owing to the chill of October. 

 Some remained entire ; others were contracting in two days ; and soon 

 after several decomposed into granular particles, as incident to the Plana- 

 riae. Then, the Animalcula infusoria are speedily generated. 



In regard to the cornute vesicle, that or one narrowly resembling it, 

 is represented in Lamouroxuv' s work on the Flexible Corallines, as distin- 

 guishing the Nemertesia Janini, the second species of his genus Nemerteaia. 

 Almost the whole descriptions of that Treatise seem to have been derived 

 from dried specimens, and possibly from very small fragments of them ; 

 whereas, in those presenting such varieties, or anomalies, as two or three 

 different shaped vesicles appearing on the same specimens, all its parts 

 must be brought into view. 



I shall merely allude to another vesicle which I was induced to as- 

 cribe to the Sertularia or Nemertesia ramosa, of this paragraph, without 

 having had leisure and opportunity to confirm the fact. Thence, on future 

 investigation, it may be found to belong to some cognate. In my specimens, 

 numerous vesicles resembling a vase with a serrate orifice, were crowded 

 together on one side of the stalk, not being disposed around it like the 

 ovate vesicle of the lobster's horn. But this contained a single large pla- 

 nula, with a ruddy tinge, about the sixteenth of an inch in length. Above 

 fifty were produced on September 13, during the course of a single obser- 

 vation. From some unknown cause, a ropy scum formed on the surface 

 of the water in the vessel containing them, which being removed, by re- 

 plenishment to overflowing, exposed slender spines with an enlarged sum- 

 mit rising from stellate roots. In 24 hours, that is on the 18th of Sep- 

 tember, a lateral bud, beside the enlargement, displayed a pale green hydra 

 with 16 muricate tentacula. The root had now partitioned into ten or 

 twelve heavy divisions, bounded by a narrow transparent margin. The 

 hydra flourished before the spine had rose three lines. But neither did it, 

 or any others generated on the same occasion, survive above three days. — 



