4l8 THE ALGAE 



It will be seen that the difference between the cis- and trans-esters 

 always makes the same total; also that except for valency 5 there 

 is always a 10/10 difference in the cis-/trans- ratio as between 

 successive valencies in gametes of the same sex. The difference 

 in ratio between male i and female i, however, is not 10/10 but 

 30/30. 



Five valencies appear to be exceptional and in other algae ex- 

 hibiting relative sexuality the number of valencies is said to be less. 

 In Dasycladus clavaeformis, Protosiphon hotryoides and Entero- 

 morpha intestinalis there are said to be three valencies in the male 

 and female gametes. Because of the different valencies various 

 types of reaction occur when gametes of different valencies are 

 mixed. These types of reaction have been classed as : 



Reaction o : No fusion of gametes. 

 Reaction i : Isolated pairs of fusing gametes. 

 Reaction 2 : Clumps of 10-20 gametes. 

 Reaction 3 : Clumps of 100 or more gametes. 



In Chlamydomonas eugametos all types of combinations between 

 male and female valencies up to 4 have been made and the results 

 are shown in Table 24. 



Table 24 



Type of reaction between gametes of different valency in 

 C. eugametos {after Moewus) 



These reaction types can be correlated with increasing ten 

 point steps from a cis-/trans- ratio of 0/0 to a ratio of 90/90 (Table 



25). 



