140 MARGARET C. FERGUSON 



the most important stage in the heterotypic division and several 

 recent writers have expressed a similar opinion. 



Page 26. The appearance of chromosomes from an " appar- 

 ently formless reticulum," described by Williams ('04) as occur- 

 ring in the first division of the tetraspore-mother-cell in Dictyota 

 is interesting in connection with the origin of the chromosomes 

 in the microspore-mother-cell in Pinus as herein described. 



Page 31. Allen ('04) has described a somewhat similar 

 method of segmentation in the first division of the microspore- 

 mother-cell in Lilium Canadense. 



Page 32. Strasburger ('04) has returned to his earlier view 

 regarding a true reducing or transverse division in the first 

 mitosis of the spore-mother-cell in plants. 



Page 32. Farmer and Moore ('03), Williams ('04), Stras- 

 burger ('04) and others now accept the fact of a qualitative 

 division in plants. 



Page 32. As a result of his recent study of Galtonia, Tra- 

 descantia, etc., Strasburger has decided that the forms of the 

 chromosomes which may occur in the anaphase of the hetero- 

 typic division are not the result of a double longitudinal spliting. 



Page 33- According to Farmer and Moore ('03) the hetero- 

 typic division in both animals and plants is characterized by a 

 transverse division. This transverse division effects the sepa- 

 ration of the two chromosomes which constitute a bivalent 

 chromosome, and is therefore a qualitative or reducing division. 



Page 34. This is in direct accord with the recent publica- 

 tions of Boveri ('04), Cannon ('03), Rosenberg ('03 and '04) and 

 others who have recently expressed themselves regarding the 

 individuality of the chromosomes. 



Page 48. Strasburger's earlier observations on the pollen- 

 grain of Picea have now been confirmed by Miyake ('03) who 

 shows conclusively that the generative cell is cut off in Picea 

 before pollination takes place. 



Page 62. In 1903 Miyake described and figured several 

 stages in the development of a single binucleated sperm-cell in 

 Picea. 



Page 63. In a note at the close of Coker's ('03) paper on 

 Taxodium he says : " Miss Ferguson confirms Blackman's ('98) 



