32 I. F. LEWIS 



In this condition the shells were left. They were not examined 

 again until June, 1913, when they were found to be bare of red 

 algae, or at least as bare as the neighboring piles. It is evident 

 that the individuals forming the abundant growth of the pre- 

 ceding September did not survive. It may be stated as a general 

 rule that the plant which has attained any considerable size or 

 which has produced reproductive bodies dies at the approach of 

 cold weather. Only the very young sporelings are able to resist 

 the changed conditions and remain dormant during the winter. 



Some of the shells, and also slivers of wood cut from the ad- 

 joining piles, were carefully examined. Small red dots were 

 found sparsely on shells and wood alike. This condition is to be 

 contrasted with that of the previous August^ when the shells 

 were abundantly covered with crowded sporelings and the piles 

 almost or entirely bare of the species under observation. On 

 examination, the small dots proved to be the tiny holdfasts of 

 species which could not be identified with the data at hand. In 

 addition to these holdfasts, there were also present on the shells 

 various brown algae and sponges. 



In July young plants of the three species employed were found 

 sparingly on all the shells and rather abundantly on the piles. 

 It is a point of special importance that these species had not pre- 

 viously been seen on the piles of the Fay Wharf, this being one 

 of the reasons why this particular spot had been selected for the 

 experiments. 



As they matured, these plants proved to be prevailingly tetra- 

 sporic, as is generally true of specimens collected at random at 

 this season. In early August they began to be replaced by sexual 

 plants, as is also true generally. In hundreds of collections made 

 in July, about ten tetrasporic plants to one sexual individual were 

 found, while in August the majority of plants collected were 

 sexual. This has been shown to be true of many other species, as 

 well as of those with which the experiments were carried out. 



From the available data the entire life-cycle of the species used 

 can be reconstructed. In July the tetrasporic plants produce 

 tetraspores in great numbers, and scattering sexual plants pro- 

 duce some cafrpospores. The carpospores germinate readily, but 



