4 HOLDEN, Abiiorinal specimens of Dictynta dichotoma. 



that " after a few divisions tlie germlings invariably died." 

 In a previous paper (Lloyd Williams, (3)) the same 

 author has also recorded various abnormalities in tetra- 

 sporic plants, among which he refers to the direct germina- 

 tion of the tetraspore mother-cell to form a small mass of 

 parench}'ma. This may subsequently " develop an apical 

 cell and grow out into an elongated germling-like branch, 



and may remain alive when the rest of the thallus has 



decayed." Further on in the same paper he states that, 

 as far as his observations go, " this mode of cell-multiplica- 



Fig. 3. Section across thallus of Didyota dichotoma, showing 

 antheridial ' sori ' and tetrasporangia in various stages 

 of development. The contents of one antheridium 

 are indicated diagrammatically, the scale being too 

 small to show detail. 



tion never follows the reduction division." It would thus 

 appear that the nucleus of the tetraspore mother-cell does 

 not invariably undergo meiotic division, but may give rise 

 to a sort of diploid gemma-like shoot. 



In the case under consideration there is, however, a 

 certain amount of indirect evidence which tends to show 

 that the parent plants were haploid and consequently that 



