IMPREGNATION AND GERMINATION OF ALG.E. 125 



isolated by the disappearance of the jelly. It will then be 

 seen that each sporule is also surrounded by a very thin 

 colourless gelatinous layer (fig. 22) ; and it will be distinctly 

 perceived that these eight portions of contents of the original 

 cell have not as yet acquired any cellulose membrane. 

 Should any douht upon this point remain, it will be wholly 

 dissipated upon close consideration of the two lowermost 

 sporules in their natural position, and which are the last to 

 leave the spore-case when its contents escape (fig. 21 a). 

 These two portions are always produced at the extremity into 

 a point, which shows the absence of a membrane with the 

 greater certainty, since the change of form into the spherical, 

 which these spores undergo when they become isolated, could 

 not take place did any membrane exist. The spermatozoids, 

 then, come into contact with these membraneless masses, 

 covered only with a thin gelatinous layer. It is these masses, 

 the " division- spores" of the Fucus, which after impregnation 

 has been effected become the young plant. The first indica- 

 tion of commencing germination in them is the formation of 

 a visible, tough membrane (fig. 23) around them, which also 

 manifestly arises from a transformation of the gelatinous laver 

 in which they are enveloped. The membrane is apparent about 

 twenty-four hours after the contact with the spermatozoids. 



So soon as the membrane is formed around the sporules, a 

 number of minute red-brown nuclear bodies, which did not 

 exist before, are visible at the periphery of the sporule, and 

 they are enclosed togetlier icith the mass of the sporule by tJie 

 newly-formed membrane loith tchose inner surface they are in 

 contact. The author never failed to observe these minute, 

 red-brown nuclei (fig. 23), in impregnated sporules which 

 afterwards grew up into young plants. They make their first 

 appearance almost simultaneously with the formation of the 

 membrane at the periphery of the sporule, and do not dis- 

 appear till afterwards, and in the further development of the 

 impregnated sporule (fig. 24). The author looks upon these 

 corpuscles, whose colour corresponds Avith that of the nuclei 

 of the spermatozoids of Fucxis, as originating in the sperma- 

 tozoids. 



The present case, tliercfore, he remarks, affords another 

 instance of what was observed in Vaucheria, viz., tliat the act 

 of impregnation does not consist in the operation of the sper- 

 matozoids upon a previously perfectly-formed cell possessing a 

 membrane — an " embryonic cell" — which would be impreg- 

 nated through its membrane, but rather in this, that one or 

 several spermatozoids enter a still membraneless, granular 

 mass, which afterwards, together with the spermatozoids, 



