140 K. Miyake, Contribut. to the Fertiliz. and Embryogeny of Abies balsamea. 



In another preparation, tive nuclear fig-ures were found in the 

 Upper part of the eg-g- in wliicli two seg*mentation-nuclei were pre- 

 paring to divide. One of the figures, which is found nearest to the 

 segmentation-nuclei is shown in Fig. 44 a, and probably represents 

 the second sperm - nucleus. The nuclear reticulum is apparently 

 resolved into chromatic threads or spirenie. Above these, three 

 groups of cliromatic spireme are found. Near the apex of the egg 

 a Y shaped nuclear figure is seen. It presents a fibrous reticular 

 structui*e and fragments of chromatic threads are found in two 

 places (Fig. 44cj. The last four nuclei above nientioned have pro- 

 bably been derived from both tube-nucleus and the nucleus of the 

 stalk-cell. 



In the case sketched in Fig. 45 two nuclei and one nuclear 

 figure were seen in the upper part of the fertilized egg in which 

 two segmentation-nuclei are dividing. Two nuclei which are located 

 about midway between the two segmentation nuclei and the apex 

 of the egg have a ]-eticulum which is somewhat fibrous in character 

 and the nuclear membranes are not very well marked, appearing as 

 if about to be dissolved. They may probably be formed by the 

 di Vision of the second sperm -nucleus. The nuclear figure mth 

 chi'omosonies collecting near the lower pole is found above them, and 

 possibly belongs to the tube-nucleus. 



Miss Ferguson ('Ol) saw such nuclear figui^es in the upper 

 part of the fertihzed egg and stated: „frequently the sperm-nucleus 

 and occasionally the vegetative nucleus attempt to divide mitotically. 

 One or two small abortive karyokinetic figures are not uncommon 

 in the upper part of the egg at the time of the division of the two 

 segmentation-nuclei." She also mentioned that the stalk-cell remains 

 for some time unchanged, and finally disintegrates without showing 

 such nuclear figui^e. She also observed ,,a well developed spireme" 

 similar to one of the figures in Fig. 46 b in the upper part of the 

 egg. Murrill ('00) found „a tripolar spindle in the position commonly 

 occupied by the second sperm-nucleus." It seems possible in the 

 case of Abies the sperm -and tube- nuclei. and the nucleus of the 

 stalk-cell divide or at least attempt to divide before they disintegrate. 

 The abnormal appearance of the nuclear figures also suggests that 

 division and disintegration are taking place at the same time. 



Miss Ferguson ('Ol) found in Pimis that in a few cases the 

 second sperm-nucleus divides amitotically, and a similar Observation 

 was made by Arnoldi ('00) in Oephalotaxus. Wuicizki ('99) found 

 that in Larix dahurica the second sperm-nucleus remains unchanged 

 for a long time in the upper part of the egg after fertilization, 

 while the vegetative nuclei soon undergoe disintegdi^ation. Coker ('02) 

 stated that in Podocarpus the ventral canal- nucleus often divides 

 amitotically in the fertilized egg. In one case, in the unfertilized 

 archegonium, he found that both the egg and ventral canal-nuclei 

 divide amitotically. I have not been able to find even a Single con- 

 clusive case of amitotic division in the egg. Only once the nucleus 

 of the ventral canal-cell was found somewhat dumb-bell shaped in 

 appearance in the tip of the egg, suggesting a possible case of 

 amitotic division (Fig. 41). 



