C YSTOSPERMEiE. 193 



is perfectly certain the usual and most frequent method of 

 reproduction of the Vesiculiferce is by means of zoospores, and 

 this fact, of which I have so perfectly assured myself, leads 

 to adoption of one of the following views — either that the 

 large, oval, or spherical bodies of the Algce, comprised in M. 

 Decaisne's class of zoosj)ores, are not in any way connected 

 with reproduction ; a view which can scarcely be regarded as 

 probable, and opposed to that entertained by M. Decaisne 

 himself; or that they as well as the zoospores do perpetuate 

 the species ; in favour of which view the evidence can scarcely 

 be pronounced sufficient to remove all doubt of its correctness. 



Link has endeavoured to establish this genus under the 

 name of Q^dogonium, which has been adopted by Klitzing, 

 who thus imperfectly characterises it. 



" Trichoma simplex, membranaceum, flaccidum. Cellulae 

 coelogonimicae, gonidia minutissima mobilia continentes. Sper- 

 matia solitaria globosa fusca, epispermo duplici hyalino cincta, 

 cellulis inclusa." 



In this description no allusion is made to the mode of 

 formation of the sporangia, and none to the ringed apparatus 

 with which each fruit-bearing cell is provided. 



Several other generic terms have been applied to certain 

 species of the genus Vesiculifera, such as Tiresias, Cadmus, 

 Zoocarpa *, &;c. but all of them, so far as I can learn, are 



* Respecting the genera (Edogonium^ Tiresias, and Zoocarpa, I have 

 obtained the following information : — In the " Dictionnaire Classique," 

 vol. xii. p. 78., Bory thus remarks on the genus CEdogonium. " The genus 

 proposed by Link under this name appears to be the same as that which 

 Vaucher named Prolifera, for which we have adopted the name of 

 Vaucheria. In the remarks on VaiicTieria, Bory states that it was wrong 

 of De Candolle to change the name of Ectosperma, which he proposes to 

 restore, and to confer the name of Yaucher on the genus Prolifera, that 

 appellation being founded in error : and Guilleman in the 16th volume, 

 p. 268., of the same work, under the head of Tiresias, observes — ' Our 

 co-labourer, Bory de St. Yincent, has established and described a new 

 genus of the family of Arthrodece and of the tribe of Zoocarpece, \\\ which 

 he indicates as the principal species the Conferva hipartita of Dillwyn 

 (a Tyndaridea .^). The characters of this genus have been explained in 

 this Dictionary, vol. i. p. 597 — 1822.' Since that time the genus has been 

 adopted by Fries, who has placed it amongst his Hydrophytes or Algce ; 



O 



