2 HOLDEN, A bnonnal Specimens of Dictyota dichotoma. 



cells, however, undergo meiotic division, this resulting in 

 a halving of the chromosome number and the consequent 

 restoration of the haploid condition in the next generation. 

 The precision with which these changes normally occur 

 naturally invests any abnormalities with a peculiar interest, 

 and it is with a record of this kind that the present paper 

 is concerned. 



During the examination of some preserved material 

 of Dictyota dichotoma with a view to the preparation of 

 sections for a senior class, two abnormal specimens were 

 discovered, in which the thallus bore not only well- 



/>i^ 



Section across thallus of Dictyota dichotoma, showing 

 the presence of oogonia and tetraspores. 



developed oogonial " sori," but also scattered sporangia 

 in various stages of development. 



The material was carefully sectioned, but was not 

 sufficiently well preserved to obtain the cytological 

 evidence necessary to settle the various points raised. 

 Future investigation of similar material, with more 

 adequate cytological preservation, will show whether the 

 thallus bearing these two kinds of reproductive organs is 

 haploid or diploid in character. 



