556 THE GAMETOPHYTE OF PSILOTUM, 



the spore-contents assume the form of a large bubble-cell, which 

 fills up the whole of the spore. 



This l)ubble-cell splits int(j two cells, whifh again subdiAide, 

 until finally eight, or more, cells are formed. The whole of the 

 protoplasm appears to be used up in the formation of these cells, 

 which are unequal in size, free, and without a trace of any other 

 cellular structure. When nearing uiaturity, some of these cells 

 may be seen outside the sp(jre-case, while others remain inside, 

 the relative inequality in size l)eing unaltered. All these cells 

 produce antherozoids in abundance. There appears to be a thin 

 deposit of gum binding the spoi-e-case and the cells to the sub- 

 stratum on which the spore grows. These cells are usually 

 spherical, easily separated, and often floating freely without any 

 trace of their having been attached. 



So far as concerns the male gametophyte of Psilotum, there- 

 fore, I may claim to have got positive results. The numerous 

 specimens I have had under observati(ni warrant the conclusion 

 that there is one kind of spore that produces the male gameto- 

 phyte; that this gametophyte consists of a series of free anther, 

 idia, and that each antheridial cell, irrespective of size, forms 

 mother-cells and antherozoids. 



The seai-ch for the female gamctoph^^te has been a nuich more 

 difiicult matter, and very disappointing. A careful look-out was 

 kept for signs of the female throughout my investigations, and 1 

 have already indicated how I was enabled to conclude that the 

 spores were dia'citnis. Curiously enough, the females were pre- 

 sent all the time, and quite as plentifully as the males. The 

 size, .shape, and colour of the peculiar structure, which ] have 

 come to regard as the female gametophyte, required at least a 

 one-sixth objecti\'e to distinguish it from small, malformed spores 

 of the normal kind, and immature spores of various shapes and 

 sizes. The presence of three or four testaceous amoebte, which 

 resembled the gauietophyte in shape and colour, two species of 

 Arcella, one Assulina, and one Euglypha, added to the confusion. 



Even after 1 had seen the female iu situ, both in its early 

 stages and in what I regard as the adult form, it required pro- 



