o/ /Ae Florideee arw? Corallineae. 119 



If iodized water be brought into contact with globules placed in 

 alcohol, we see a certain number of the granules situated on 

 the line of meeting of the two liquids suddenly burst, and throw 

 out around them their contents, reduced to the form of very 

 small granules, which become blue, whilst the torn membrane 

 is of a pale violet colour. 



When heated in water to near 158° Fahr. the globules swell, 

 become partially dissolved, and at the same time acquire a fine 

 violet colour. A drop of sulphuric or hydrochloric acid immedi- 

 ately gives a violet or blue tint to the granules which have been 

 reddened by iodine, but at the same time dissolves them partially, 

 swells them up, and tears them. Potash also dissolves them. 

 Hypochlorite of lime alters them rapidly ; in twenty-four hours 

 there remain of most of the granules only the outermost layers 

 isolated from each other ; in thirty-six hours all has disappeared. 

 Acetic acid and ammonia have no action upon them. 



Thus these globules present all the characters of starch in 

 their form, structure, and optical properties, and in the action 

 exerted upon them by hot water, acids, and alkalies ; but they 

 differ from amylaceous grains as these are defined, by their 

 acquiring a red colour with iodine. However, they are easily 

 converted into common starch under the ordinary influences 

 which I have just described, but with the condition that they 

 become disorganized and partially dissolved. This difference, 

 which is not sufficient to warrant the employment of a new 

 name, leads to the supposition that we have to do with a hydro- 

 carbonated principle isomeric with cellulose and starch, but in- 

 termediate between them by its cohesion. 



After the details into which I have entered with regard to 

 Halopithys pinastroides, Kvitz., I can only say a few words of 

 the starch-grains of other Floridese ; but I must make special 

 mention of the Pohjsiphonice, because the amylaceous formation 

 in them presents a new character, which, indeed, occurs very 

 frequently elsewhere, but less evidently. In Polysiphonia ni- 

 grescens, Grev., which I shall take as an example, the joints of 

 the axis never contain anything but a finely granular liquid ; 

 the flattened cells of the siphons, on the contrary, and the corti- 

 cal cells each contain a coherent mass of spherical globules, which 

 entirely fills them. These globules, the diameter of which is 

 pretty uniformly 0*007 millim., do not scatter themselves in the 

 liquid which bathes the sections, but the entire masses issue in 

 their cells. By applying pressure to them we may succeed in 

 breaking them up into several fragments; but their elements, 

 which have a strong mutual adherence, do not separate; when 

 their margin is carefully examined, they are seen to be surrounded 

 by a continuous membrane, which is rendered yellow by iodine ; 



