TUBULARIA. 67 



is better preserved, the parts more accessible, and by immediate trans- 

 ference, it can be always kept in the purest medium. 



Several white specks among the twigs issuing from the branches then 

 became perceptible by the naked eye, which, under the microscope, proved 

 to be small solid pear-like substances of bluish-grey colour. Thence I 

 proposed to denominate them pyrula. 



Thinking little more of the matter at the moment, I concluded they 

 might be regenerating hydra, as not unusual with different zoophytes. 

 But my attention was soon arrested by the position of some as if seated 

 on the long neck of the living hydra. I could not doubt that one neck 

 sustained three, and that elsewhere a cluster of four appeared at the extre- 

 mity of a twig then vacant of a hydra. Further investigation ascertained 

 the following facts. 



Minute pyriform bodies, as above specified, are dispersed on the stalk 

 of different parts of the Tubularia, at considerable intervals ; sometimes 

 three are together, sometimes two opposite to each other ; or only one 

 terminates a twig, where it might be readily supposed a regenerating 

 hydra. — Plate XI. figs. 5, 6, 7. Each pijrulum is affixed by its own dis- 

 tinct pedicle, at first of some length, but gradually shortening as the 

 remainder becomes more globular, or flattens. In a few days, the whole 

 may be compared to the opening bud of a white rose. — Fig. 8. 



Now the dilatation and collapse of the subject commence ; convulsive 

 struggles ensue ; four pair of long rough muricate organs resembling ten- 

 tacula, or ciliary processes, are gradually unfolded ; and after what seems 

 repeated severe and protracted exertions, a perfect animal of great trans- 

 parence is liberated as a Medusa, suspended amidst the waters. — 

 Figs. 9, 10. 



This Medusa resembles a large transverse section of an ovoid, not 

 half a line in diameter, the sides of excessive tenuity, the tentacula, or 

 ciliary organs, four or five times as long as the diameter of the ovoid, and 

 quite flexible. I conjectured there might be an orifice in the upper sur- 

 face, and that some stump or particular organization by which it was pene- 

 trated, and remaining behind, the animal amidst its struggles was kept in 

 its place. It is the upper surface which is that in application or adhesion, 



