426 HOFMISISTKR, ON 



of the latter into the corpusculum which is to be impreg- 

 nated. These cells, which now become very easily dis- 

 integrated, contain numerous spindle-shaped motionless 

 bodies, consisting of a substance coloured brown by iodine. 

 These bodies are short in Thuja and elongated in Juniperus 

 (PL LXIV, fig. 3 4 ).* 



The first change which is visible in the corpusculum after 

 the entry of the pollen-tube, is an increase in the granular 

 matter contained in the larger germinal vesicle. This cell 

 gradually moves towards the lower end of the corpusculum, 

 against which it ultimately presses itself (PI. LXV, fig. 10). 

 The larger germinal vesicles which lie in its way are dis- 

 placed and dissolved ; the smaller ones remain unaffected. 

 Since any successful longitudinal section through the 

 endosperm of an impregnated germinal vesicle lays bare 

 many different stages of development of neighbouring 

 corpuscula, there cannot, in the great number of cases 

 which are brought into comparison, be any doubt as to the 

 order of their succession. Even in Juniperus, especially in 

 Juniperus communis, the smaller impregnated germinal 

 vesicles which are immediately attached to the end of the 

 pollen-tube, very often possess firm membranes composed 

 of cellulose. 



In all the Coniferse the impregnated germinal vesicle, 

 which is pressed into the bottom part of the corpus- 

 culum, divides by a transverse septum, so far that is as 

 this division has not already taken place during its descent. 

 The two daughter- cells — of which the upper is the larger 

 one and the lower more rich in protoplasm — divide by lon- 

 gitudinal septa : in some cases this division occurs only in 

 the lower one (PI. LX, fig. 1 1 ; PI. LXI, figs. 3—7). Shortly 

 afterwards the septum which divides the upper, more empty 

 cell or cells, from the rest of the cavity of the corpusculum, 

 is dissolved. The two longitudinal portions of the lower 

 daughter-cell of the germinal vesicle form the first rudiment 

 of the pro-embryo of the Coniferse. Its formation is always 



* It might easily be imagined that the cellules produced in the interior of 

 the ends of the pollen-tube of Coniferee might produce spermatozoa. My obser- 

 vations however have hitherto only yielded negative replies to the question, as 

 will be seen by the account given above. 



