I02 MARGARET C. FERGUSON 



in Cycas in 1898 and more recently in Ginkgo ('01), and Arnoldi 

 ('00) in Cephalotaxtis. Blackman ('99) devoted several para- 

 graphs to a discussion of metaplasm, as it manifested itself in 

 the egg-nucleus of Pinus sylvestris. He found that it was 

 present in the ^^oung nucleus in the form of granules, but that 

 it later united with the chromatin to form the nuclear reticulum. 

 Chamberlain ('99) does not recognize the presence of this sub- 

 stance in the egg-nucleus in Pinus Laricio ; and there is no 

 evidence of its existence in the sexual nuclei of the species of 

 pines which I have studied. 



According to Wilson ('99) "protoplasmic substances repre- 

 sent the active, metaplasmic structures the passive elements " of 

 the cell. During the development of the egg-nucleus in the 

 species of pines which have formed the basis of these studies, 

 there is never any deposit within the normal nucleus of a granu- 

 lar substance ; but the linin, as already stated, becomes very 

 abundant. Just what proportion of it is active in cell division, 

 we are unable to say. Without doubt a large part of the linin 

 merges into the cytoplasmic network during the first segmen- 

 tation of the oosphere-nucleus, but even so, it can not be classi- 

 fied with the passive elements of the cell. 



Blackman ('98) wrote: "The stage in which the nucleus is 

 found in a position between the apex and the center of the egg 

 is rarely met with" ; and Chamberlain ('99) stated " that in over 

 three hundred preparations, less than a dozen " show early 

 stages in the development of the egg-nucleus. During the 

 course of these investigations upon the pines, about four thousand 

 preparations, representing many thousand archegonia, have been 

 studied, and no developmental stage has been more frequently 

 met with than that by which the nucleus assumes its central posi- 

 tion in the egg. Such an appearance as that illustrated by 

 Chamberlain in his figs. 18 and 19 has been observed in both 

 the young and the mature egg-nucleus, in the conjugating nuclei, 

 and also in the various nuclei of the proembr^-o. They have 

 been wholly disregarded in the present discussion of the matura- 

 tion of the ^^^t for, in my material, these figures, and also 

 Blackman's figure 11, would be interpreted as representing dis- 

 integration stages. Every step has been repeatedly traced from 



