K. M i y a k e , Contribut. to the Fertiliz. and Embryogeny of Abies balsamoa. 137 



the nuclear cavity, but witliout any chromatic substance as seeii in 

 the other case (Fig. 22). 



Miss Ferguson ('Ol) observed the nuclei similar in structme 

 to those mentioned above, but she did not figui^e them. She wrote : 

 „Such an appearance as that illustrated by Chamberlain in bis 

 Figs. 18 and 19 has often been observed in both the young and the 

 mature egg-nucleus, in the conjugating nuclei, and also in the various 

 nuclei of the proembryo. They have been wholly disregarded in the 

 present discussion of the maturation of the egg, for, in our material, 

 these figm-es, and also Blackman's Fig. 11, would be interpreted 

 as representing disintegration stages." The nuclei of this kind 

 often have irregulär concavities or indentations on the upper side. 

 One as sketched in Fig. 23 was observed several times, and suggests 

 the crater-like depression described by Ikeno (' 98) as formed in the 

 egg-nucleus of Cycas before fertilization. 



After the formation of the ventral canal-cell, the vacuoles, if 

 there are any left, entii^ely dissappear, and an increase in the number 

 of the proteid-vacuoles takes place. When the egg approaches 

 maturity, granules in the proteid-vacuoles beconie larger and often 

 seem to unite into one large granule. Besides these proteid-vacuoles, 

 uumerous granules varying in size and having the same appearance 

 as the granules in the proteid-vacuoles can be seen scattered 

 throughout the egg -cyptoplasm. Thus the cyptoplasm of the egg 

 which presented a finely granulär appearance in its early stages of 

 development now shows a coarsely granulär structure. 



The mature egg-nucleus is surrounded by a clear area of cyto- 

 plasm which is much more finely granulär in structui'e and takes 

 less stain compared with the rest of the egg-cytoplasm (Fig. 18). 

 This appearance can akeady be observed before the egg-nucleus 

 reaches the centre of the egg and while it is still immatui-e 

 (Figs. 4, 17). 



The number and arrangement of cells forming the neck, vary 

 somewhat in different archegonia. The neck of a mature arche- 

 gonium in Abies halsamea more commonly consists of three or four 

 tiers of cells, with four cells in each tier, as observed by Stras- 

 burger (' 69) in Abies pectinata. Not infrequently a neck with two 

 tiers of cells was met with, and sometimes each tier was found 

 with two cells only. The neck -cells usually contain a number of 

 stai'ch-grains, as was observed by Strasburger ('69) in Abies pecti- 

 nata. Abies seems to be the only genus in the Abietinae in which 

 starch-grains are found in the neck -cells. I do not know of any 

 similar instance described in any other group of the Conifers. 



Some of the sheath- cells of the full-grown archegonium often 

 show early stages of division, although very few of them seem to 

 reach the stage in which a distinct spindle is to be seen. Many of 

 them showed the chromosomes clear and distinct. I have counted 

 their number in several cases, and twelve, or approximately twelve, 

 were always found (Fig. 26), as in Pinus (Blackman ' 98, Chamber- 

 lain ' 99, Miss Ferguson 'Ol). 



In several cases I found an extra nucleus near the tip of the 

 egg, just beneath the ventral canal-cell. It is somewhat larger than 

 the nucleus of the ventral canal-cell, and its structure and staining 



