1920] Setchell-Gnrdner : Chlorophyceae 249 



coasts of North America where the Massachusetts coast experiences a 

 much colder winter and spring season than do western coasts of North 

 America of the same zones. On the Pacific Coast, so far as our knowl- 

 edge goes, the species is confined to the Bering Sea and adjacent por- 

 tions of the Alaskan Peninsula where the summer temperature of the 

 surface waters seldom, if ever, rises above 10° C. 



2. Enteromorpha micrococca Kuetz. 



Frond 1-5 cm. long, 1-5 mm. wide, tubular or compressed, simple 

 or slightly proliferous at times, much curled and twisted ; cells angular, 

 4-5|U, diam., in no definite order ; membrane 15-20/x thick, with distinct 

 inner hyaline laj^er. 



Growing in the upper littoral belt, on rocks and on woodwork. 

 From Alaska (Dutch Harbor) to Mexico {fide Collins, loc. cit.). 



Kuetzing, Tab. Phyc, vol. 6, 1856, p. 11, pi. 30, f . 2 ; Collins, Green 

 Alg. N. A., 1909, p. 204 ; Setchell and Gardner, Alg. N.W. Amer., 1903, 

 p. 211 ; Saunders, Alg. Harriman Exp., 1901, p. 411. 



2a. Enteromorpha micrococca forma subsalsa Kjellm. 



Plate 16, fig. 1 



Frond compressed, much contorted, with numerous, patent or 

 uncinate, shorter or longer branches from the margin, the latter again 

 branched, all broad at the base and tapering to a point. 



Growing on stones in the littoral belt. Alaska (Skagway) to Wash- 

 ington (Puget Sound). 



Kjellman, Alg. Arctic Sea, 1883, p. 292, pi. 31, f. 1-3; Collins, 

 Green Alg. N. A., 1909, p. 204, Mar. Alg. Vancouver Is., 1913, p. 102 ; 

 Setchell and Gardner, Alg. N.W. Amer., 1903, p. 211 ; Collins, Holden 

 and Setchell, Phyc. Bor.-Amer. (Exsicc), no. 1068 (fresh water). 

 Enteranwrpha nmiinia Setchell and Gardner, Alg. N.W. Amer., 1903, 

 p. 213 (in part) ; Collins, Holden and Setchell, Phyc. Bor.-Amer. 

 (Exsicc), no. 912. 



Enteromorpha micrococca is, in typical form, a low plant forming 

 a layer on rocks and woodwork high up in the littoral belt. It is to 

 be distinguished by its small cells, not arranged in longitudinal rows, 

 and its thicker membrane which is reinforced by a hyaline layer on 

 the inside. In its ordinary marine habitat, it seldom shows any 



