and Plants confounded with than. 203 



lamellae as in the Halimedece. Over these plates are large 

 vesicular cells. Schvveigger terms these cells filaments, 

 because, probably, he did not employ a sufficiently strong 

 magnifying power. When the calcareous matter is not 

 completely removed, the cells are observed to be filled. 

 The geuus Liagora is distinguised from that described, by 

 the absence of articulations. The trunk of the plants of 

 this genus is ramified and covered with lime. The Liagora 

 complanata (Agardh), or the Fucus lichenoides (Esp.) is the 

 only species of this genus known to Link. It is compressed, 

 much ramified, with acute branches, green upon one side, 

 and calcareous on the other. When the plant is digested 

 for some days in muriatic acid, all the substance presents 

 the appearance of being divided into two large cells. By 

 the microscope, we observe, that these cells are united 

 by a membrane. If only a portion of the lime is removed, 

 and the plant be examined, we find a membrane of which 

 the side is covered with vesicles, and the rest of the 

 lime is dispersed in small portions over the surface of 

 this membrane. Agardh united the Fucus distentus with 

 this kind of Liagora, although it certainly does not belong 

 to it. 



The cells of the Fuci, which differ much from the vesicu- 

 lar cells of which we have been speaking, resemble those 

 of the superior orders of plants. 



The vesicular structure united in most of the Halimedece 

 with the lamellar ramifications, constitutes, in general, the 

 essential organization of those Algoz which approach them 

 in their external and internal structure. 



The Acetabulum Mediterraneum, or A Marinum (Schweig- 

 ger), or rather, the Acetabularia of Lamouroux is a very 

 singular body which resembles the Agaricus, or stalked 

 Helotium. It consists of a round top, with a pedicle. It is 

 covered with lime, which may be removed by an acid, when 

 we wish to study its structure. The top is formed of tubes 

 which are first straight in the centre, and increase towards 

 the circumference. In each tube there is a canal which 

 often appears as if displaced ; it is filled with a green and 

 granular matter. A similar tube is observed in Conferva 

 filled with the same substance as in the Spyrogyri. We 

 might say, therefore, that this body is a Conferva, if we 



