168 KAARE MÜNSTER STRØM. 



106 a. forma. 



A form of E. elegans as recorded by Printz (Ghloroph. Norw. 

 Tab. I, Fig. 9.) occurred in one sample. 



107. Euastrum binale. (Turp.) Ehrbg. 

 Very frequent, and often in abundance. 



107 a. var. Gutwinskii. Schmidle. 

 Not uncommon. 



107 b. var elobatum. Lund. 

 Rare. 



107 c. forma. 



Long. 10,5 f.1, lat. 9,5 u, lat. isthm. 3,5 f.i. A very minute 

 form. PI. in, Fig. 6. 



108. Euastrum denticulatum. (Kirch n.) Gay. 

 General, and often in abundance. 



109. Euastrum Tuddalense. sp. nov. 



Cells minute, about IVo times as long as broad, deeply 

 constricted, sinus narrowly linear, semicells quadrate-pyra- 

 midate, almost four-lobed, the lateral margins being deeply 

 incised, apex broad and rounded, with an open, but rather deep 

 incision. There are four short and blunt, very delicate spines, 

 one lateral on each lobe. Side view of semicells almost circular, 

 with the apex as a conical projection, the cell-wall with thicke- 

 nings in the middle, and rough apex. Vertical view elliptic, with 

 an inflation on each side, and the lateral margins slightly 

 crenulate, the inflation being smooth. Ratio of axes about 1,2:1. 

 Size: long. 20— 20,3 ^^ lat. 14,4— 15,6 ^^, lat. isthm. 4,7 ^i, 

 crass. 10,6—11,8 /t. 



This is a characteristic species, which can not easily be 

 confused with any other. It occurred in some quantity m one 

 or two samples. PI. Ill, Figs. 2 — 4. 



110. Euastrum pectinatum. Breb. 

 var. inevolutum>. W. & G. S. West. 

 General and often in abundance. 



