April. 1019.1 THE OERMTNATION AND DEVELOPMENT. 75 



they entirely disappear from the substratum and anywhere 

 else. The same thing is repeated every year in the same place. 



Where do the carpospores go after they are liberated from 

 the mature frond ? Thuret^-* observed that the artificially 

 cultured carpospores mostly went to decay, onlv a few of them 

 having germinated into protonema-like bodies. Berthold^'' 

 experienced the same thing in Porphyra leucosticta and could 

 observe only a little advanced stage of development in P. laci- 

 niata. From what he observed in the field, he regarded these 

 sporelings as abnormal, due to the unfavourable conditions for 

 development of the spores under the artificial culture. He 

 assumes that the carpospores will germinate very slowly in 

 nature and pass their resting period without a considerable 

 change in form. 



As a matter of fact, we could not hitherto find the spores 

 floating on, or suspending in the water about the culture- 

 ground during Ma\^-September ; nor could we succeed in finding 

 the spores in the bottura-soil of the- ground. 



In the lecture delivered in the Royal Dublin Society on 

 December 16, 1913,^^ I called this into question and remarked : 

 " At present we must frankly admit ignorance on this point." 



About the time when I gave the lecture at Dublin, Seki 

 was making researches on the physiology and biology of Por- 

 phyra leucosticta var. elongata ( = P. tenera Kjellm.) in Tokj'o 

 Bay. The report was published in Japanese in the Suisan 

 Kenkiushi, Vol. IX, No. 11, November 1, 191i. In it he 

 stated that he could not find its spores in the sea in spite of 

 various efforts since September, 1913. He tried artificial culture 

 of the spores which he obtained from plants collected on April 

 12, 1914. He used beakers as culture apparatus and filled 

 them with a seawater of the specific weight 1.018. This is a 

 water of about medium salinity at the culture grounds of 

 Porphyra in Tokyo Bay. 



1) Thttret : Etudes Phycologiqaes, 



2) Berthold: Bangiaceen, p. 19. 



3) Yendo : On the Cultivation of Seaweed, with Special Accounts of their 

 Ecology. (Economic Proceeding of the Royal Dublin Society. Vol. II. No. 7, 

 March, 1914. 



