on some Marine Animals and Plants, 125 



portion of the plant quite fresh from the shore. It remained 

 for several minutes quiescent, and then some of the divisions 

 of the frond exhibited sudden startings like spasms. I had re- 

 peatedly before been amused by watching this appearance on 

 a larger scale though with the naked eye, by putting a bunch 

 of the plant in a basin of water. When so placed it soon 

 assumes the appearance, to a considerable degree, of being 

 animated ; instantaneous startings are observed in the chief 

 branches, along with lateral motions of the smaller branches, 

 which are seen to move towards, or to diverge from, the 

 former. 



But the cause of these startings, and of the consequent mo- 

 tions of the branchlets, was more obvious, by observing what 

 passed in 2ijportion of the plant laid in a thin stratum of water 

 on a plate, as above alluded to. The colour of the specimen 

 was, when so placed, homogeneous throughout ; but whenever 

 the startings took place, a change began to take place also in 

 the colour. The joints of the plant are filled with the co- 

 loured fluid ; and while it is in the salt water the septa, or 

 partitions between the joints, remain entire; but when the 

 influence of the fresh water is felt, the septa burst, and the 

 contents of one joint are exploded into the next, the colouring 

 matter, at the same time, losing its uniform tint, and curdling 

 into grains, or granular points of a dark hue, as if concen- 

 trating itself in order to part from the fluid through which it 

 had been before uniformly diffused. From the violence with 

 which the contained fluids are urged through the partitions of 

 the joints, breaches form in the sides, also, of some of them, and 

 then at every new spasm a quantity of the colouring matter is 

 hurried through these lateral breaches into the circumambient 

 water. The latter explosions present under a common mag- 

 nifier an extremely interesting appearance. They are instan- 

 taneous ; and when the projected fluid has attained its extreme 

 distance, the colouring matter suddenly settles in a cloud of 

 dark grains, so as to give not an unlively idea of a bomb-shell 

 in the act of bursting. Repeated explosions take place from 

 the same breach, but at very uncertain intervals. Sometimes 

 several occur in rapid succession, and again half a minute or 

 more intervenes between them. It appeared to me that each 

 explosion from the lateral breaches was caused by a new rup- 

 ture between some twojoints. 



These observations I repeated many times, and I here state 

 what I remarked as exactly as is in my power. They are 

 only, however, what I observed with a common magnifier, or 

 with the naked eye ; but, perhaps, a more patient research, 



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