339 . 



living in water, and that, except for the influence which that medium exercises 

 on them,- they would be identical with Lichens on the one hand, and with 

 Fungi on the other. The method under which the genera should be arranged, 

 almost every observer having a method of his own, is a question still to 

 settle ; but in this place we have chiefly to consider the more remarkable 

 facts connected with their organisation. Those who wish to. make the order 

 a special study will do well to take the .excellent Species Algarum of 

 Agardh for their guide, and to study the papers of Bory de-St. Vincent, 

 and Fries, for general ideas, and that most beautiful of all books, the 

 AlgcB BritanniccB of Dr. Greville, for the application of them to the Flora 

 of this country. 



Those who have ever examined the surface of stones constantly moist- 

 ened by water, the glass of hothouses, the face of rocks in the sea, or 

 of walls vfhere the sun never shines, or the hard patlis in damp parts 

 of gardens after rain, cannot fail to have remarked a green mucous 

 slime with which they are covered. This slime consists of Algae in their 

 simplest state of organisation, belonging to the genera Palmella, Nostoc, 

 Red Snow, and the like, the Nostochinse of Agardh, or Choetophoroideae 

 of Greville; they have been called Chaodinese by Bory de St. Vincent, 

 ■whose account of them is to the following effect: — The slime resembles 

 a layer of albumen spread with a brush ; it exfoliates, in drying, and finally 

 becomes visible by the manner in which it colours green or deep brown. 

 One might call it a provisional creation waiting to be organised, and then 

 assuming different forms, according to the nature of the corpuscles which 

 penetrate it or develope among it.. It m.ay further be said to be the origin 

 of two very distinct existences, the one certainly animal, the other purely 

 vegetable. This matter lying among amorphous mucus consists in its sim- 

 plest state, of solitary, spherical corpuscles, (such as are figured by Turpin in 

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

 common green crust upon old pales, Palmella botryoides) ; these corpuscles 

 are afterwards grouped, agglomerated, or chained together, so producing 

 more complex states of organisation. Sometimes the mucus, which acts as 

 the basis or matrix of the corpuscles, when it is found in water, which is the 

 most favourable 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 vege- 

 table corpuscles. Often, however, they assume a milky or ferruginous ap- 

 pearance ; and if in this state they are examined under the microscope, they 

 will be found completely filled with the animalcules called Navicularise, 

 Lunulinse, and Stylariae, 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 \vay to such a nidus, and have they hindered 

 the developement of the green corpuscles? Is the mucus in which tl>ey lie 

 the same to them as the albuminous substance in which the eggs of many 

 aquatic animals are deposited ? 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 animal- 

 culae called- Vibrio tripunctatus and bipunctatus by Muller, strung end to 

 end. See Ferussac's Bulletin, Feb. 1824. He particularly applies this re- 

 mark to Monema comoides. 



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

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

 containing pulverulent or corpuscular matter in the inside, and become what 



