18 ZOOPHYTES. 



tinctly under observation, seem, as in others, to be below. When free 

 their course is quick, perhaps not less than from ten to twelve feet in a 

 minute. Sometimes on reaching the surface of the water, they accumu- 

 late there in stationary groups, as if incapable of descent, like the smaller 

 Crustacea, and various other subjects. Though endowed with considerable 

 vigour, perhaps their natatory organs fall into such a position, or so large a 

 portion is dry, that their mechanical influence on the water is unavailing 

 or lost. Then the corpuscula project partly above the surface. By a 

 lens they appear smooth and shining ; and when taken between the fingers 

 the cluster feels soft, and is crushed without any sensible resistance. — 

 Fig. 4. 



After two or three days or more have elapsed, the motion of this cor- 

 pusculum, which I cannot hesitate to conclude an animated being, relaxes ; 

 it becomes stationary, and adheres to the vessel below. Next ensues the 

 prolongation of one part, rather pointed at first, fig. 7, but afterwards be- 

 coming obtuse, fig. 8. There are two prominences seen beside the pro- 

 longation, fig. 9, which are gradually moulding into form as the central 

 yellow nucleus is refining ; fig. 10. In seven or eight days from the depo- 

 sitation of an adult specimen of the product, the nascent Flustra, after the 

 preceding modifications, has become a single hydra, together with three 

 originating leaves^ of which that in the middle advances more speedily 

 than its fellows. The young animal is light grey, vivacious, provided with 

 ten or twelve percussive tentacula. Its neck and body are of considerable 

 len°th, but the darkness of the cell precludes observation of the interior ; 

 fig. 11. Still farther diffusion of the cellular portion ensues, but I have 

 been unable to preserve the nascent specimens long enough to follow its 

 progress. — Fig. 12. 



When floating groups are brought before the microscope, prolonga- 

 tion of the extremity is discovered in some of the corpuscula; which 

 shews that the germinating principle is not entirely dependent on adhe- 

 sion below. But being now repressed by an unfavourable position, it 

 ceases to advance. 



Increment of the leaf proceeds by the cells advancing beyond the 

 the margin. — Fig. 13. 



