July. 1917. j z. TENBO:— NOTES ON ALGAE NEW TO JAPAN. VII. 191 



Ag. f. genuina Hauck. In the forma referrable to var. arbuscula 

 J. Ag. I have met with them rather occasionally. It is there- 

 fore to be noticed that the corticating filaments are not ex- 

 ceptional in a certain form of B. plumosa of the Atlantic as 

 Collins thinks. 



Setchell^ himself admits that the specific limitation be- 

 tween B. corticulans and B. plumosa is on the degree of the 

 cortication at the basal parts of branches and the robustness 

 of frond. He 2J even notes that his species " may only be an 

 extreme form of B. plumosa." Collins 3 ' also expresses no less 

 doubt about the specific importance of these characters. Still 

 that the cortication is limited to the "robust and large forms" 

 of B. plumosa Ag., though not constant, may not be looked 

 over in the classification of Bryopsis, species of which are 

 distinguished from one another by very subtle points. I choose, 

 therefore, to mention Setchell's species as a forma under 

 B. plumosa in similar signification like its other formae. But 

 whether this corticated forma may coincide with an already 

 described forma or species, (f. genuina Hauck, B. pennata 

 J. Ag. and B. Kosae J. Ag. are to be suspected), or may be 

 taken as distinct one I am not able to ascertain now. It is 

 not unreasonable also to doubt that the cortication might be 

 only a state, frequently or usually met with, in the robust 

 forms of more than one species. 



Locality. Hidaka Prov.(!); Iburi Prov. (X. Takahasiii); 

 Rikuzen Prov.(I); Hitachi Prov.(!); Cape Inuboi(!) ; Kazusa 

 Prov.(!). As far as known to me, this form is limited to the 

 southern end of the Behring Current on the Pacific coast. 



Distribution. Atlantic coasts of Europe and North America; 

 Mediterranean Sea; West coast of North America, from Van- 

 couver Island to California. 



i) Phyc. Bor.-Amer., No, 020. 



•_; Betch. el Gahdk. : \]g. N. \v. Amer.j p. 230. 



':,) (iron Alg. N. Amer., \>. 401. 



