672 



SEXUALITY 



possible combinations. As appears in Table 7, no two of the sexes are 

 exactly alike. For example, the sexes I have designated A and B differ 

 in that A will copulate with C while B will not; A and C differ in 

 that they copulate with each other, although they are alike in their re- 

 actions to the other four sexes; and so on. The direct inference naturally 

 drawn from these observations is that there are six diverse sexes in this 

 group of races, and I have therefore designated them by six different 

 letters. The question of whether such multiple sex systems can be reduced 



Table 7: Breeding Relations in Chlamydomonas paradoxa and 

 C. pseudo paradoxa* 



* + — copulation; — = no copulation. Data by Moewus (Hartmann, 1934). The designations 

 of the sexes differ from those used by Moewus. 



to two sexes, male and female, will be taken up later. Moewus holds 

 that they can and designates them otherwise than I have done in Tables 

 7, 8, and 9. 



A similar system of multiple sexes is indicated by the breeding rela- 

 tions in the second group of species, as shown in Table 8, constructed 

 from the data of Moewus (Hartmann, 1934; Moewus, 1936, 1937b, 

 1938a). Two sexes have been isolated in C. sp. (cocc/feraP), C. hraunl'i, 

 and dresdensis, six in C. paupera, and eight in C. eugametos. Not all of 

 these are diverse, however. The two in C. dresdensis are the same as two 

 in C. paupera and two in C. eugametos; four in C. eugametos are reduci- 

 ble to two diverse sexes identical with two others in C. paupera; and 

 the remaining two in C paupera are identical with two others in C. 



