that the polarity of the egg is so firmly established by four hours 



exposure to daylight that it cannot be changed. 



/ The f<ct that Ku cuy^evan es c ens is a monoecious specita 

 makes it impossible to tell the exact time of fertilization, 

 but it occurs soon after the eggs escape from the oogonial 

 sac into the water. The sperms at this time can ba seen 

 escaping fro-n the antheridia and swimming rapio.i./ around the 

 eggs, then scattering as, presumably, one of than succeeds in 

 entering. The first oross-wp.li can "03 seen very plainly 

 twenty- four hours after the cultures are started. The 

 mucilage accompanying the eggs caused them to aether e so 

 firmly to the distil that it is not necessary to use f sol^d 

 media to ke p the sporelings from being displaced when the 



cultures are moved to the microscope sjage for examination. 



However U-Hha eggs germinated behind the color screens^ 



and illuminated for the first eight hours after fertilization. 



- 



showed 4r orientation with respect to the direction of the- light. 

 They grew 'corually as if in darkness with the direction of the clear - 

 age plane following no rule and the rhizoids extending in every dir- 

 ection. Evidently the intensity of the light was too low to have any 

 effect, or the time or duration of the stimulation was not right. 



Attempts to increase the intensity by bringing the cultures closer 



that is. within about seventy-five centimeters 



to the wrcTfre suited invar iably in the death of the spores Before any 



A placed (5"cm. from the naked arc 



development occured. A cooling device^ consisting of a layer of water 



A 



(p cm. thick between two glass plates, reduced the temperature 

 from 29 to v*s*^y-+*^=^fa^^\\\\\'r^,^f^iFrjrtp^/ but al so A r educed 

 che intensity of "#Te light that no orientation was obtained. Attempt* 

 to use direct sunlight as the source of light also caused the rapid 

 death of the eggs, presumably on account of ',he high temperature 

 accompanying it. 



Future work on this puoblem auafr therefore involve the use 



of stronger sources of illumination ajdn cooling devices to 



"-a an ^ 



