48 ZOOPHYTES. 



which, in several different species of animalcula, are obscurely indicated 

 somewhere below, because their position is never freely exposed. Their 

 view is always intercepted. 



The shape of these alcyonic corpuscula, independently of reciprocal 

 differences, is extremely variable, but their colour is uniformly white. 



In a week the number of gemmules exceeded 100. The specimen 

 had been locked up in the dark, but now, after an hour's exposure to a 

 moderate degree of light, at least 150 more had left their nidus, and swam 

 with great activity. These had been obviously elicited by the influence of 

 the light, as I have had occasion to remark of some other zoophytes. The 

 cilia were in rapid motion, whether serving as natatory organs in aiding the 

 animal's progression, whether promoting respiration, or any different pur- 

 pose, as this motion does not cease when the gemmules remain stationary, 

 and are occupied about other objects. However, it is probable that when 

 they tumble amidst the water, it is not by the exercise of the cilia, but 

 from some different force. 



Meantime numerous hydrse were now and afterwards displayed from 

 this specimen, fig. 5, which was transferred to a larger vessel, that the 

 gemmules might be left for observation, continued until the middle of 

 April. 



As these corpuscula seemed to escape through the skin of the surface, 

 wherein I could neither discover a previous aperture, nor the site of the 

 hydrse, the propagation here may be compared to that of the Cristatella 

 or Alcyonella, as subsequently explained. Thirty or forty corpuscula 

 would issue thus on exposure to the light. 



Next their motion relaxes ; they become stationary, and are affixed 

 in adhesion to the surface, whereon they repose. A thin diffusing margin 

 then enlarges the circumference, rendering their appearance very like 

 . minute, delicate, white shells, fig. 14; and they grow gradually more at- 

 tenuated, fig. 15. 



Those gemmules quitting the parent specimen, fig. 5, on February 

 20, had become motionless on the 27th of the same month ; and on 

 March 3, the first of the nascent hydrae was displayed from one of the dif- 

 fusing spots, which much resembled a shell. Next day other three were 



