GERM-CELL HISTORY IN THE BROOK LAMPREY 95 



of the stimulus exercised by the older individual over the sex of 

 the larva. 



Among plants there seem to be many cases which indicate 

 that every individual possesses a double sex potentiality. It 

 appears that in some of the lower types of plants which are nor- 

 mally dioecious, the organs of the opposite sex can be made to 

 appear on all the individuals under proper culture conditions; 

 that is, the male plant will produce female organs and vice versa. 



Bordage ('98) cut back the apex of young male plants of Carica 

 papaya just before the appearance of the first male flowers. Lat- 

 eral branches arose below the cut, and these produced female 

 flowers and fruit. Strasburger ('00) found that the smut Ustil- 

 ago violacea caused the dioecious plant Melandryum album to 

 produce the opposite sex organs; that is, the male organs appeared 

 on the female. The pistils remained undeveloped, while the 

 normally rudimentary anthers grew large and produced pollen 

 mother cells. Later, Strasburger ('09) came to the conclusion, 

 from a consideration of many evidences, that sex determination 

 in plants cannot be the result of mendelian segregation. He says: 

 "Ich bin nach alledem der x\nsicht dass alle Versuche, die Ge- 

 schlechtsbestimmung getrenntgeschlechtlicher Organismen auf 

 Mendelische Spaltungsregeln zuruckzuflihren, erfolglos bleiben 

 werden" (p. 17). Strasburger also did not consider the so-called 

 sex chromosomes as true chromosomes. He says: ''Demi nicht 

 nur zeigen sie ein eingeartigen Verhalten, sondern auch ihre 

 Beseitigung aus den Geschlechtszellen ist moglich, was fiir 

 Trager von Erbeinheiten nicht zulassig ware." Should they be 

 proved to stand in some relation to sex, they might yet be indi- 

 vidual linin bodies ''die aber nicht Pangene fiihren, sondern der 

 Aufnahme des liber das Geschlecht bestimmenden Stoffes dienen" 

 (p. 22). 



It may be suggested in this connection that other bodies are 

 present in the cell which may become unequally divided during 

 mitosis. This is true of plasmosomes, which may not always dis- 

 solve and become diffused throughout the cell before division. 

 It may be equally true of mitochondria and other cytoplasmic 

 bodies. Such an hypothesis has been advanced by Schaudin 



JOURNAL OP MORPHOLOGY, VOL. 35, NO. 1 



