Nov., 1914.] Stamens of Smilax herbacea. 365 



change the nucleous disappears. It is not possible to discover 

 whether it was dissolved or disintegrated into smaller bodies and 

 ejected into the cytoplasm. The cytoplasm at this stage has a 

 very spongy appearance, but no micronucleoli were seen in it. 



In the mother star of the first division the chromosomes 

 are attached to the spindle fibers near their free ends with the 

 head of the loop extending outward as found by Schaffner in 

 Lilium philadelphicum (11) and by Miss Hyde in Hyacinthus 

 (3). There is a gradual shortening of the spindle fibers and at the 

 same time the chromosomes uncoil and pull apart at the outer 

 head of the loop or at the point where fusion took place during 

 synapsis. From drawings of metakincsis it will be seen that 

 the transverse splitting of the chromosomes of Smilax herbacea 

 is not simultaneous as is found in many plants. (Fig. 27). After 

 metakincsis the chromosomes are arranged around the poles 

 forming the daaghter stars of the first division. (Fig. 2S). There 

 is also a perceiptible increase in the density of the cytoplasm in 

 the ec|uatorial region where in a short tJme a distinct cell plate 

 is seen. By the time of the complete formation of the cell plate, 

 the spindle is no longer visible and a new nuclear membrane 

 is laid down around the daughter masses of chromatin material 

 thus forming two new cells very similar to the parent cell, but 

 much smaller. With the formation of the new nuclear membrane, 

 it is also foimd that the nucleoh of the daughter cells are beginning 

 to appear. The chromatin material in these daughter cells 

 does not undergo such changes as were evident in the nuclei of 

 the sporocyte, but the newly formed chromosomes are massed 

 together not to form a continuous spirem, but an irregularly 

 shaped mass in which the individual chromosomes may be 

 distinguished. (Fig. 29). 



The daughter cells do not immediately separate, but may be 

 seen still clinging together after the second division is well 

 advanced. In the second division the chromosomes are attached 

 to the spindle fibers in the equatorial plane by the head of the 

 chromosome, having the free ends extending outward. (Fig. 30). 

 The separation of the chromosomes at this division is along the 

 longitudinal split. After the second metakincsis we find the 

 two daughter stars with the distinct chromosomes (Fig. 31) 

 which were readily counted in several preparations from the 

 polar views. The number was found to be twelve. (Fig. 32). 



The cell plates of this division soon appear and a new nuclear 

 membrane is evident in each daughter cell around the rather 

 small chromosomes which become more or less crowded together 

 and connected by fine connecting strands. All the tetrads 

 appeared to be normal, there being no such irregularities found 

 as shown by Fullmer in Hemerocallis and by Miss McAvoy in 

 Fuchia. 



