56 ZOOPHYTES. 



On the 6th of October, a colony which invested a shell of considerable 

 dimensions was suspended in still another vessel of sea-water. After the 

 lapse of fourteen days, several of the corpuscula from the colony were 

 found below, elongated to minute hydra of various extent. One of these 

 exhibited twelve obtuse prominences, from an enlarging head. — Fig. 9. 

 In three more days, another was adhering to a watch-glass, without any 

 perceptible diffusing root. This was very minute, pure white, with seven 

 originating tentacula, beyond which the summit was much prolonged. — 



Fig. 10. 



The tentacula of adult hydra are susceptible of such extension, that, 

 owing to their slenderness, they assume almost a silky appearance. The 

 summit is also susceptible of considerable prolongation. 



Probably the complement of tentacula augments with age. 



Nothing more satisfactory can be therefore said of the propagation 

 of the Hydra squamata, than that the nascent animal comes of an ovum 

 contained in a vesicle borne externally by the adult. 



Interspersed with the hydra of almost every colony, are many dark, 

 rough, irregular substances, tending to a conical form, and much resem- 

 bling the product denominated Alcyonidium echinatum. But no symptoms 

 of animation being betrayed by any portion of them, I doubt much 

 whether they belong to the animal creation. 



Specimens of the Hydra squamata have survived during seven months. 



If ever occurring in shallow waters, they seem to be always carried 

 thither by the temporary occupants of shells. 



Plate XVIII. Fig. 1. Hydra (coryna) squamata investing a shell. 



2. Hydra? enlarged. 



3. Portion of the colony, fig. 1, enlarged ; head a. 



4. Prolific vesicles on a hydra. 



5. Prolific vesicles on another stem. 



6. Spherules from the vesicles. 



7. Spherules from the vesicles. 



8. Spherules. 



9. Nascent hydra?. 



10. Nascent hydra, farther advanced. 



All the preceding figures, excepting fig. 1, are enlarged. 



