65 



primary sporogenous tissue multiply rapidly, forming, 

 however, only sporogenous cells is practically complete 

 when the primary tapetal layer begins to divide. In 

 cross section the sporogenous cells. The division of 

 these cells are about four times as numerous as the 

 primary sporogenous cells. They form a somewhat 

 cylindrical mass of tissue which becomes separated 

 from the tapetum. While the sporogenous cells are 

 enlarging and differentiating the division of the 

 primary tapetal layer takes place, the cells of which 

 by dividing by periclinal divisions form a wall 

 layer and an inner layer. The inner layer divides 

 into two. forming an intermediate or middle layer and 

 the layer which developes into the peripheral part of 

 the tapetum. The axial part of the tapetum in Hemer- 

 ocallis is derived from the adjacent general tissue in all 

 cases. 



About the time the cells of the sporogenous tissue 

 are in the spore mother cell stage, the middle wall 

 layer breaks down and disintegrates. The wall of the 

 mature anther consists of the thick walled endothecial 

 cells, having thickened reticulate bands, and of the dis- 

 integrated epidermis. 



ADDITIONS TO THE LIST OF OHIO 

 DRAGONFLIES. 



By James S. Hjne. 



Previously, ninety-seven species of Ohio dragontlies 

 have been reported, and published in the proceedings 

 of this association. The past Summer's collecting has 



