CYSTOSPERMEiE.

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is perfectly certain the usual and most frequent method ofreproduction of the VesiculiJercB is by means of zoospores, andthis fact, of which I have so perfectly assured myself, leadsto adoption of one of the following views — either that thelarge, oval, or spherical bodies of the Algce, comprised in M.Decaisne’s class of zoospores, are not in any way connectedwith reproduction; a view which can scarcely be regarded asprobable, and opposed to that entertained by M. Decaisnehimself; or that they as well as the zoospores do perpetuatethe species; in favour of which view the evidence can scarcelybe pronounced sufficient to remove all doubt of its correctness.

Link has endeavoured to establish this genus under thename of CEdogonium, which has been adopted by Kiitzing,who thus imperfectly characterises it.

“ Trichoma simplex, membranaceum, flaccidum. Cellukeccclogonimicte, 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 offormation of the sporangia, and none to the ringed apparatuswith which each fruit-bearing cell is provided.

Several other generic terms have been applied to certainspecies of the genus Vesiculifera, such as Tiresias, Cadmus ,Zoocarpa *, &c. but all of them, so far as I can learn, are

* Respecting the genera CEdogonium, Tiresias , and Zoocarpa, I haveobtained the following information : — In the “ Dictionnaire Classique,”vol. xii. p. 78., Bory thus remarks on the genus CEdogonium. “ The genusproposed by Link under this name appears to be the same as that whichVaucher named Prolifera, for which we have adopted the name ofVaucheria. In the remarks on Vaucheria, Bory states that it was wrongof De Candolle to change the name of Ectosperma, which he proposes torestore, and to confer the name of Vaucher on the genus Prolifera, thatappellation being founded in error : and Guilleman in the 16th volume,p. 268., of the same work, under the head of Tiresias , observes — ‘ Ourco-labourer, Bory de St. Vincent, has established and described a newgenus of the family of Arthrodece and of the tribe of Zoocarpece , in whichhe indicates as the principal species the Conferva bipartita of Dillwyn(a Tyndaridea ¥). The characters of this genus have been explained inthis Dictionary, vol. i. p. 597—1822.’ Since that time the genus has beenadopted by Fries , who has placed it amongst his Hydrophytes or Algce;

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