1 74 SAUNDERS [4 10 ] 



Frond 40-60 ;JL thick, dark green, becoming brownish or blackish 

 when dried, not adhering to the paper ; cells in cross-section usually 

 longest at right angles to the surface of the frond. 



In the Kukak Bay specimens the frond is about 40 /* thick, and the 

 cells are nearly square in cross section, agreeing with the typical M. 

 fuscum. In the Lowe Inlet specimen the frond is 30 /j. thick, the cells 

 in cross section somewhat rounded, agreeing with the form known as 

 M. splendens. The color however is duller than usual in that form. 



Monostroma vahlii J. Ag. 



Kukak Bay (316). 



Frond persistently tubular, torn at the top so as to form a flat mem- 

 brane only at a quite late stage ; thickness of membrane 15-25 fj. ; cells 

 about 1 2 ;JL in cross section, somewhat arranged in series when seen 

 from the surface. 



This species has much resemblance in habit to the genus Entero- 

 morpha, at least when young. 



Monostroma grcenlandicum J. Ag. 



Kukak Bay (346). 



Frond filiform, opening only at the extreme top, when in fruit ; 

 thickness of membrane 2530^ ; cells roundish-angular seen from sur- 

 face, radiately elongate in cross-section. 



Externally the frond of this species is that of a slender, unbranched 

 Enter omorpha, but the structure is that of Monostroma. It has here- 

 tofore been found only in the Arctic region and along the Atlantic coast, 

 from Greenland to Nahant, Massachusetts. The specimens from 

 Kukak Bay have cells little more than half the size of those in Green- 

 land and New England specimens, otherwise there is no difference. 



Ulva lactuca rigida (J. Ag.) Le Jolis. 



Frond usually ovate when young, later becoming of indefinite shape, 

 rather firm. 



Common in quiet pools, Virgin Bay, Prince William Sound (278) ; 

 Shumagin Islands (396). 



A very common species, varying in form, texture and dimensions, 

 distributed all over the world. 



Ulva lactuca myriotrema Le Jolis. 



On rocks and algaB, Sitka (133). 



Frond pierced with numerous irregular holes. Rather a form than 

 a definite variety. 

 Enteromorpha linza (L.) J. Ag. 



Yakutat Bay (232). 



