CYSTOSPERMEiE.

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will be seen, is not in all respects inaccurate, though still,for the most part, very erroneous: —

“ When the Prolifera are ready to reproduce, cylindricalenlargements are seen to arise in the length of the filaments,which one would take for knots, if the plants were not arti-culated or chambered. These bourrelets, at first but littleapparent, soon increase in size, and finally become coveredwith a pulverulent material, which is formed either by refusematter which floats in the liquid, and which has been re-tained within the elevations, or of a material which is secretedby the Conferva. When this powder has remained sometime upon the enlarged part of the stem, a number of fila-ments are seen to issue from it, which form at first littlerounded heads. Unfortunately this powder at the sametime that it seems to favour the increase of the young Con-ferva baffles greatly the observer. He is able to see butlittle of the first developement of the plant, and in conse-quence is not able to judge, whether it issues from the sur-face of the enlargement or from the centre: whichever itmay be, the young filaments extend themselves round all thecircumference, where they form as it were a tuft of hairs.Little by little their cells begin to be marked out; soon theirtubes resemble in miniature those of the great Prolifera.Lastly, they go and form elsewhere a new individual, like tothat from which they took their birth : but I acknowledge,”says Vaucher, “that I have not seen this separation, althoughI have no doubt but that it really takes place.”

What Vaucher regards as the young proliferous offspring,are doubtless to be regarded as parasitic growths, to which theConferva are peculiarly liable, more especially when they areconfined for a length of time in small vessels of water.

Two other species of this group have been referred byMeyen to a genus Hempelia, which he instituted for them, agenus even more erroneously defined than that of Prolifera,already noticed.

“ Hempelia. — Thallus simplex, membranaceus, septatus,requalis vcl inaequalis. Fructus tcrminalis est, capsula sub-