AND GERMINATION OF ALG^E. 131 



wliilst in the sporangium of Vaucheria only a single, large 

 quiescent spore is produced which is impregnated through a 

 solitary orifice in the membrane of the sporangium, in the 

 sporangia of Achlya numerous smaller quiescent spores arise, 

 and the supposed impregnation takes place through numerous 

 openings in the membrane of the sporangium, whose number 

 probably corresponds with that of the spores. Tlie analogy 

 between the two cases is further rendered more apparent by 

 the existence of very slender ramifying branches springing 

 from the parent tube in close contiguity to the sporangium 

 containing the quiescent spores, and which are so closely 

 applied to the membrane of the latter as apparently to be 

 adnate to it. The analogy between these ramules which were 

 first pointed out by Braun, and the " hornlet" in Vaucheria 

 cannot be overlooked. The author has often noticed them, and 

 it has appeared to him that where they were in contact with the 

 membrane of the sporangium, these ramules throw out short 

 papillary lateral shoots, which were protruded through the 

 openings of the membrane of the sporangium and caused the 

 close adhesion of the ramules to that body. 



Although, at present, it is but a mere supposition that the 

 spermatozoids of Aclilya are developed in these armules, the 

 existence of the openings through which the spermatozoids 

 may reach and impregnate the contents of the sporangium, 

 has at least been discovered ; and it has also been shown that 

 the quiescent spores of Achlya germinate in the same way as 

 do those of Vaucheria. 



Among other fresh-water Algre which, besides the asexual 

 mode of multiplication by zoospores, also present quiescent 

 spores ; the author proceeds to communicate some observa- 

 tions, made upon CEdogonium, Bulbocha'te, and Coleochcete. 

 With respect to the micropyle of the sporangia in CEdogonium. 

 he remarks that before the formation of the spore in the parent 

 cell, a great accumulation of its contents takes place as in 

 VaucJieria ; and on many occasions in CEdogonium tumidulum, 

 he has witnessed the sudden rupture of the membrane of the 

 sporangium, on one side, through which the granulous and 

 cutaneous layers are protruded (fig. 26.) But the latter does 

 not, as in Vaucheria, throw off a portion, but is again with- 

 drawn ; and the whole contents of tlie cell, not yet surrounded 

 by a membrane, are converted into the well-known quiescent 

 spore of CEdogonium, most probably with the co-operation of 

 spermatozoids which have entered through the opening in 

 the sporanqimn thus formed. The opening in CEdogonium is 



K 2 



