335 



du Museum, vol. 18. t. 5. ; and as may be easily seen in the common green 

 crust upon old pales, Pahnella botryoides) ; these corpuscles are afterwards 

 grouped, agglomerated, or chained together, so producing more complex states 

 of organization. Sometimes the mucus, which acts as the basis or matrix of 

 the corpuscles, when it is found in water, which is the most favorable medium 

 for its developement, elongates, thickens, and finally forms masses of some 

 inches extent, which float and fix themselves to aquatic plants. These masses 

 are at first like the spawn of fish, but they soon change colour and become green, 

 in consequence of the formation of interior vegetable corpuscles. Often, how- 

 ever, they assume a milky or ferruginous appearance ; and if in this state they 

 are examined under the microscope, they will be found completely filled with 

 the animalcules called Navicularia?, Lunulinre, and Stylaris, assembled in such 

 dense crowds as to be incapable of swimming. In this state the animalcules 

 are inert. Are they developed here, or have they found their way to such a 

 nidus, and have they hindered the developement of the green corpuscles'? Is 

 the mucus in which they lie the same to them as the albuminous substance in 

 which the eggs of many aquatic animals are deposited 1 At present we have 

 no means of answering these questions. According to M. Gaillon, many of 

 these simple plants are certainly nothing but congeries or rows of the singular 

 and minute animalcule called Vibrio tripunctatus and bipunctatus by Muller, 

 strung end to end. See Ferussac's Bulletin, Feb. 1824. He particularly ap- 

 plies this remark to Monema comoides. 



Another form of Alga?, one which may be considered a higher degree of 

 developement of the last, is that in which they assume a tubular state, con- 

 taining pulverulent or corpuscular matter in the inside, and become what are 

 called Conferva?, or, as M. Bory styles them, Arthrodiea?. These, which com- 

 prehend true Conferva?, Oscillatorias, and many Diatomea?, are thus spoken of 

 by the acute botanist last mentioned : The general character of Arthrodiea? 

 consists in filaments, generally simple, and formed of two tubes, of which one, 

 which is exterior and transparent, offers no trace of organization to the most 

 powerful eye, so that it might be called a tube of glass, contains an inner arti- 

 culated filament filled with coloring matter, often almost imperceptible, but at 

 other times very intense green, purple, or yellowish; these compound filaments 

 present to the astonished eye the strangest and most different phenomena, all of 

 which have the plainest characters of animal life, supposing that animal life is 

 to be inferred from motions indicating a well marked power of volition. The 

 Arthrodia tribe usually inhabit either fresh or sea-water, and several are com- 

 mon to both. One of them, but a species referred to the tribe with some uncer- 

 tainty, the Conferva ericetorum, grows on the ground, but in places that are 

 very damp, and often inundated ; others among the Oscillating species cover the 

 humid surface of rocks or earth, and the interstices in the pavement of cities ; 

 some even grow in hot springs of a very high temperature. (Ulva thermalis 

 lives in the hot springs of Gastein in a temperature of about 117° Fahrenheit. 

 Ed. P. J. 4. 206.) The most remarkable are, 1st. The Fragillarias, to which 

 Diatoma and Achnanthes belong ; these, when combined in the little riband- 

 like threads which are natural to them, have no apparent action ; but as soon 

 as the separation of the joints takes place, a sort of sliding or starting motion 

 may be seen between them. 2dly. The Oscillarias, some of which have an 

 oscillatory movement, extremely active and perceptible ; and the Ulva laby- 

 rinthiformis and Anabaina, which, -with all the appearance of a plant, has, ac- 

 cording to Vauquelin and Chaptal, all the chemical characters of an animal. 

 33ly. The Conjugata?, the filaments of which separate at one period, and unite 

 again at another, and finally, by a mode of coupling completely animal, resolve 

 themselves into a single and uniform being ; and 4thly, the Zoocarpeae, most 

 extraordinary productions, in which the animal and vegetable nature follow 



