384 Bibliographical Notices. 



bear a very striking resemblance. The resemblance of these bodies 

 to what Agardh calls antheridia is still more striking, as I am en- 

 abled to assert from specimens oi Polysiphonin fruticnlosa and P. fas- 

 tigiata, on which they had been observed by Mrs. Griffiths, and which 

 have been communicated by Mr. Berkeley. It is this resemblance, 

 doubtless, which has led Meneghini to give the same name to the 

 organs we are considering in the genus Mesoglcea. Whatever be 

 their function (I am inclined to consider them myself as gemmae), 

 they are placed in the genus under consideration either at the base 

 of the radiating threads or at the extremity of a branch of greater 

 or less length proceeding from this base. In comparing them to 

 the siliquse of Ectocarpus we have sufficiently noted their structure, 

 which is well described in the work of Meneghini. As to their form, 

 it varies within certain limits, for they are sometimes oval, ovali- 

 lanceolate, or very slender and elongato-lanceolate. In M. Leveillei, 

 of which the younger Agardh makes his genus Liebmannla, but which, 

 as it appears to us justly, Meneghini comprises in the genus Meso- 

 glcea, they have two or four horns at their summit ; but these divi- 

 sions of the granular mass are included in a common envelope. 

 Sometimes they are concealed by the radiating filaments, sometimes 

 they exceed them by half their length. 



" We now come to Chordaria. The structure is not exactly the 

 same, though there is a great affinity between the two genera. The 

 cells which form the axillary system of the frond, and which form 

 the greater part of its diameter, are united end to end so as to com- 

 pose tubular filaments, which are cylindrical, diaphanous, articulated, 

 and which decrease in diameter as they approach the circumference. 

 Exactly in the centre (for it is possible to isolate the one set of fila- 

 ments from the other) these filaments are disposed longitudinally, 

 following the axis of the frond ; but the further they are from the 

 centre the more their diameter decreases, and when they arrive at 

 the circumference their frequent anastomoses have reduced them to 

 a network of irregularly polyhedral cells, the more external of which 

 give rise to the radiating tissue. The texture of which we have just 

 sketched the description, but of which good figures alone can give a 

 just notion, has the greatest analogy with that of certain Floridete ; 

 it is such that in a transverse section it might be called cellular ; and 

 in fact towards the circumference, that is to say, between the axile 

 tissue and the radiating filaments, it can scarcely be considered other- 

 wise. The horizontal filaments spring then from the exterior cells 

 of this kind of intermediate network, and if, instead of being free from 

 any adherence, they were soldered together, there would be an almost 

 perfect resemblance with other genera with a continuous frond. They 

 are clavate, articulated and moniliform ; their last articulation, which 

 is also the largest, is sometimes spherical, sometimes cuneiform. 

 This latter conformation arises from the circumstance, that at first 

 the filaments are all of the same length ; they are almost adherent 

 one with the other at their apices, absolutely in the same way as the 

 paraphyses of Laminariete, to which they may well be compared, 

 though these latter are simple and not septate. It is at the base of 



