THE GREEN ALGAE OP NORTH AMERICA 21 



24. Filaments 56 M diam. 21, M. Boodlei. 



24. Filaments 10-13 f- diam. 22. M. Transeaui. 



25. Spore with slightly tumid sides. 23. M. tumidula. 



25. Spore with strongly concave sides. 25. M. gracilli ma. 



Page 124, after description of MOUGEOTIA ROBUSTA, add, 



Var. BIORNATA Wittrock in Wittr. & Nordst., Alg. Exsicc., 

 No. 651, 1884. Mesospore yellow-brown, strongly scrobiculate ; 

 epispore verruculose internally ; filaments 22-30 p. diam., spores 

 30-36 X 42-47 p.. Charleston, 111., Transeau. Sweden, Ceylon. 



After description of M. GENUFLBXA, add, 



Var. GRACILIS (Kiitz.) Reinsch, 1867, p. 215 ; M. gradlis 

 Kiitzing, 1845, p. 221. Smaller throughout; filaments 15-24/1 

 diam., spores 24-30 p. diam. Charleston, 111., Transeau. 



Europe. 



Page 127, after description of M. CALCAREA, add, 



23. M. TUMIDULA Transeau, 1914, p. 297, PI. XXVIII, 

 fig. 4. Vegetative cells 6-8.5 X 70-120 p, diam., zygospores 

 quadrate, somewhat tumid, 22-26 X 20-30 //., elliptical when 

 seen from the side, angles retuse, median membrane distinctly 

 but minutely scrobiculate. Charleston, 111., Transeau. 



24. M. BICALYPTRATA Wittrock in Wittr. & Nordst., Alg. 

 Essicc., No. 741, 1886; De Toni, 1889, p. 722. Vegeta- 

 tive cells n-12 p. diam., 3-9 diam. long; conjugating cells 

 slightly genuflexed ; spore ellipsoid or subellipsoid, transverse, 

 33-38 p. max. diam., 25-28 p. min. diam. ; epispore brownish, 

 thickened at each pole ; mesospore brown, smooth. Carp Lake, 

 near Mackinaw, Mich., Transeau. Sweden. 



Resembles M. calcarea, but differs by the more ellipsoid 

 spore, and darker epispore with calyptras. 



25. M. GRACILLIMA (Hass.) Wittrock, 1872, p. 40; Tran- 

 seau, 1917, p. 225 ; Staurocarpus gracillimus Hassall, 1845, 

 p. 185, PI. VII, fig. 6; Staurospermu'm gracilli mum De Bary, 

 1858, p. 81, PI. VIII, fig. 12. Cells 5-7 p. diam., 8-20 diam. 

 long ; spores quadrate (sometimes triangular) about 25 p. wide, 

 sides deeply concave, angles retuse, median membrane finely 

 granulate. Twin Lakes, Mich., Transeau. Europe. 



Page 129. Note, Printz, 1914, p. 18, considers Chlamy- 

 domonas communis Snow to be not the same as C. com munis, 

 Perty, and substitutes C. Snowii Printz. The name C. eriensis 

 proposed by Printz in place of C.globosa Snow, is unnecessary, 

 as C. globulo&a Perty does not invalidate C. giobosa Snow. 



