SEXUALixr I2;r the lower crtptooamia. 73 



in its interior. It then becomes detacliecl from the parent plant 

 by the decay of the membrane of the sporangium, and after some 

 time suddenly resumes -ts green colour and grows into a young 

 VaucJieria, exactly resembling the parent plant. 



Before dismissing Vauclieria, we may mention that fifty years 

 before Pringsheim's publication, Yaucher had suggested the sexual 

 nature of the horns, which he considered to be the anthers of the 

 plant through which the pollen was discharged. 



Dr. Pringsheim's observations on VaucJieriaj were shortly 

 afterwards followed by those of Cohn upon Sphceroplea annulina.^ 

 This somewhat rare Conferva was found by Dr. Cohn, covering 

 a field of potatoes which had been overflowed by the river Oder. 

 It forms long filaments, composed of more or less elongated 

 cellules placed end to end. The endochrome of some of these 

 cellules becomes transformed into a number of small spherical 

 bodies, consisting of a green substance, with some grains of starch. 

 Each of these bodies is clothed with a delicate smooth layer of 

 plastic matter, but not with a cellulose membrane. They are called 

 by Cohn ]^rimor dial-spores. During, or before the formation of 

 these primordial-spores, the membrane of the cellules, in which they 

 are contained has become perforated with minute apertures. At the 

 same time the colour of the contents of other cellules of the same 

 filament changes from green to a reddish-brown, and the contents 

 themselves become transformed into an innumerable multitude of 

 cylindrico-elon gated corpuscles, which escape through small aper- 

 tures in the membrane of the cellules. These corpuscles, which are 

 in fact the spermatozoa of the plant, enter the cellules, which con- 

 tain the primordial spores, by means of the apertures existing in the 

 membrane of the latter cellules. One or two of the corpus- 

 cles attach themselves by their cilia and beak to the end of the 

 primordial spores and remain attached, after which the latter speedily 

 assume a true cellular membrane. Thus, as Dr. Cohn remarks, we 

 distinguish in the component cellular tissue of Splicer opJe a male 

 cellules and female cellules, which may be called antheridia and 

 sporangia, and we recognize the fact, that in the impregnation, if not 

 of the Algse generally, at least in that of the EucacesB, Vaucherise, 

 and SphcEvoplea, the one essential circumstance, viz. the direct 

 contact of spermatozoids with a primordial cell as jet devoid of 



« See Ann. cles So. Nat. xx. 4, Ser. Vol. v. p. 188. 



