52 THE BOTANICAL MAGAZINE TVoi. xxxvi. No. 425. 



in the development of the ovule. In some cases it is associated with 

 the growth of the megaspore which is seen to become greatly 

 enlarged. Its nucleus at first increases decidedly in size, ana* this is 

 followed by a massing of the chromatic material, and then its final 

 dissolution. Such megaspores never divide and finally appear as 

 empty sac, often quite equalling in size that of the normal embryo 

 sac. In other cases the abnormality is associated with the chalazal 

 region and with the integument. In both of these regions the cells 

 and intercellular spaces become infiltrated with some product of the 

 degenerated protoplasm, as is often seen in pathological tissues. 



In other cases the abnormality arises at a later stage in the 

 development of the ovule. In this instance tbe egg apparatus and 

 polar nuclei are nearly normal, with the exception of the synergids, 

 one of which, it will be seen, is greatly enlarged. The five antipodals 

 have also become much distended and are characterized by extremely 

 delicate walls and chromatic material in various stages of degenera- 

 tion. 



These manifestations of abnormality appear to be associated 

 with the sting of insects which deposit their eggs in the ovary. At 

 least no departure from the normal has been as yet observed in the 

 ovaries not so affected. The insects deposit their eggs at various 

 points on the ovary, but usually in the vicinity of the style. This 

 sting causes a minute outgrowth that seems at first to be a 

 rudimentary style, but this growth is not associated with any 

 modification in the development of the cells of the ovary wall 

 adjacent to the sting. It is to be noted, however, there is a dif- 

 ference in the sizes of the ovaries. These affected ovaries are 

 materially larger than the normal ones. 



It is also possible that the stimulus generated by the germina- 

 tion of the insect's egg may be the cause for the development of the 

 third style and stigma noted previously. Perhaps, we have here an 

 illustration of the reappearance of ancestral characters quite com- 

 parable to the reversional features associated with injury (Jeffrey, 

 1917). 18 It would also seem probable that this same stimulus affects 

 the ovule and may account for the various types of abnormality 

 reported above. An early deposit of the egg may entirely inhibit 

 the development of the megaspore while a later sting would produce 

 the abnormal antipodals as described above. In cases, where 

 fertilization has been already effected, the stimulus may result 

 in the various types of polyembryony reported above, (Treub, 



