216 ZOOPHYTES. 



one presenting such a remarkable deviation from the nature of the pro- 

 geny discharged by the vesicles of the various Sertularian tribes. But I 

 was unable to recognise any error, either in the previous existence of the 

 Medusa within the vesicle, or in its liberatiou from it. I have seen the 

 same repeated several times, though at distant intervals ; the last occasion 

 being in July 1840, when a number of vesicles happened to be under ob- 

 servation, all of the same character. 



One Medusa at the very bottom of a vesicle had there developed 

 prematurely. It was distinctly observed clasping the tentacula below, 

 while its escape from above was precluded by the intervention of others 



still immature. 



The vesicles in progress, fall and empty, are represented figs. 4, 5, 6, 7. 



When originally observing this animal, before ascertaining its origin, 

 I had bestowed the name Tintinnabulim on it, from its resemblance to a 

 hand-bell; and I believe that its general aspect will justify such an appellation. 

 It is of some importance to find familiar objects for illustrating those un- 

 known. The body resembles a minute watch-glass, half a line in diame- 

 ter, bordered by a pendent marginal fringe of about 23 muricate tentacu- 

 lar organs issuing from an enlarged root, and nearly as long as the diame- 

 ter of the disc. A central prolongation below corresponds to the proboscis 

 of the Medusa, which is thus seen while the animal suspends itself in 

 equilibrio among the water. When reversed, it appears like a crest on a 

 convex surface. Four lines with enlarged extremities, diverge from the 

 base of the proboscis ; likewise four lines at right angles seem present 



above. — Figs. 8, 9. 



The animal is whitish or almost transparent It swims by jerks, or 

 bounds like the various species of Medusa?, from collapse of the body, 

 perhaps aided by the tentacular organs. It pursues all directions, rising, 

 falling, or remaining stationary in equilibrio. Like a group of the Medui-a 

 bifida, these creatures narrowly resemble a flock of minute birds wending 

 their course through the expanse of the firmament. 



This animal courts the light. 



In the progress of evolution they rise upwards in the vesicle, and in 

 as far as I could discover, the tentacular organs protrude first, in which 



