Dr. Pringsheim on the Germination of Alga. ^4)7 



meter, and furnished with two unequal cilia. Contempora- 

 neously with the development of the spermatozoids in the horns, 

 the contents of the capsules, or spore-fruits, become accu- 

 mulated towards the beak-like summit, which opens at the same 

 time that the spermatozoids are set free by the bursting of the 

 membrane at the apex of the horn. Vast numbers of these 

 little bodies make their escape, some already free, others engaged 

 in mucus. The free ones spread in all directions with a rapid 

 movement ; great numbers, twenty, thirty or more, make their 

 way into the opening of the spore-fruit, coming into contact 

 with the tough mucilaginous layer bounding the contents. After 

 a time a distinct membrane appears all over the mass of contents 

 of the spore-fruit, converting them into a free cell, the spore, 

 and the author states that he several times saw a largeish colour- 

 less corpuscle inside the mucilaginous coat of the contents ; he 

 believes this to have been a sperm atozoid which had penetrated 

 into the mass. The process as here described is therefore the 

 impregnation of a mass of contents by a spermatozoid, and a 

 subsequent formation of the cell-membrane of the spore. An im- 

 portant incidental point here is the confirmation of the view re- 

 cently set forth by the author, that the primordial utricle of 

 Mohl, the protoplasmic layer forming the external boundary of 

 the mass of contents, does not exercise a secreting function, pro- 

 ducing the cellular membrane on its surface, but becomes ac- 

 tually transformed into the latter^ 



The new spore does not at once fall from the parent plant ; 

 its green contents grow paler and at last become colourless, with 

 the exception of one or more largeish dark brown bodies. When 

 it has totally lost its colour, it falls away through the decompo- 

 sition of the membrane of the spore-fruit. Some months later 

 the spore again resumes its green colour, germinates and grows 

 out into a filament resembling the parent. 



FyCUS VESICULOSUS. 



The author next gives an account of his observations on the 

 impregnation of Fucus, which agree with those lately published 

 by Thuret in the ' Annales des Sciences Naturelles.' The pro- 

 cess closely resembles that just described in Vaucheria in its 

 essentials, since it consists of the advent of a quantity of sper- 

 matozoids to a spore, at that moment consisting of a proto- 

 plasmic mass clothed only by its primordial utricle, the penetra- 



* This view is elaborately worked out in his recent work, ' Unter- 

 suchungen iiber den Bau und die Bildung der Pflanzenzelle, pai't 1. Ber- 

 Un,'1854. . . . 



