24 AllT. 1-. K. YE\1)0. 



obtuse or truncated at the apices. They arc transformed from 

 the terminal segments of the branches. In the majority of cases 

 a small but remarkable vesicle is found at the point of meeting 

 of the two adjacent fertile segments, giving to the receptacles 

 the appearance of having started from the top of the vesicle. 



Remark on the affinity and relation to other species. Tiie 

 three formée above mentioned undoubtedly belong to one species. 

 On the southern end of Hokkaido as well as on the Pacific side 

 of northern Honshu we find /. typica only. But as we proceed 

 northward, the chance of meeting /. Babingtonii increases, and 

 in the north-eastern parts of Hokkaido /. japonica predominates. 



The fronds of /. typica attain the largest size with propor- 

 tionally thick segments. In some segments the breadth measures 

 one centimeter, while in the other two it seldom exceeds half a 

 centimeter. The high tide forms of /, japonica are indistin- 

 guishable from the young shoots of /. typica and tlie forms 

 intermediate between these two fornue exhibit various modifications 

 of f. Babingtonii. 



The material from which Harvey described Fucas Wrightii 

 was sterile and the exact systematic position of the species has 

 hitherto been in doubt. De Toni^^ suspected it to belong to 

 Ascophyllnm, while he transferred Fucus Babingtonii to the 

 genus Pelvetia. The vesicles, however, of Fucus Wrightii, or 

 Pelvetia Wrightii f. typica as it is here called, are never normal 

 and hence the reference of the plant to Ascojjhylluni is not 

 acceptable. 



On examining the conceptacles of/, typica and /. japonica 

 I was able to ascertain that each oogonium contained two oospores, 

 and that the essential characters of theYeproductive organs proved 



1) Syll. Alg. TIT. p. 200. 



