iz TUFTS COLLEGE STUDIES, VOL. IV, No. 7 



57. Fertile cells little if any swollen. 32. S. Weberi. 



57. Fertile cells distinctly swollen. gft. 



58. Cells 9-23 M diatn. 59. 



58. Cells 24-33 M diam. 62. 



59. Inflation cylindrical. 34. S. groenlandica. 



59. Inflation rounded or tapering at the ends. 60. 



60. Cells 12 M diam. or less. 28. 5. fenuissittia. 



60. Cells 15 M diatn. or more. 61. 



6l. Chromatophore broad ; cells 3-8 diam. long. 29. />. inflata. 



61. Chromatophore slender ; cells 10-25 diam. long. 30. S.Spreeiana. 



62. Fertile cells with quadrate swelling. 31. S. quatirafa. 



62. Fertile cells with rounded swelling. 63. 



63. Spore o%'oid, 30-36 M diam. 33. S. Grtvilltana. 



63. Spore ellipsoid, ends more or less pointed, 32-45 M diam. 



53. S. Farloii'ii. 



64. Cells 35 M diam. or less. 35. S. Hassallii. 



64. Cells 39-42 M diam. 65. 



65. Fertile cells shortened and swollen. 36. S. insignis. 



65. Fertile cells with quadrate swelling. 52. S. rcetangularis. 



66. Chromatophores quite broad. 10. A" decimina. 



66. Chromatophores very slender. 63. S. irrtgularis. 



Page 71 of supplement, cancel beginning, " Page 107, for No. 

 34" and all of page 72 to line ending "23. S. NBGLBCTA." 

 Page 107, under S. LONGATA, cancel P. B.-A., No. 510. 

 Page 108, under S. PORTICALIS, cancel P. B.-A., No. 365. 

 After description of S. CATENABFORMIS, add, 



Var. PA UVULA Transeau, 1914, p. 292, PI. XXVI, figs. 3-4. 

 Filaments usually scattered ; vegetative cells 20-24 X 50-105 /*, 

 chromatophore single, making 1-6 turns; fertile cells inil.it.. 1 .. 

 up to 37 M; conjugation mostly lateral, sometimes scalariform ; 

 spores yellow, elliptical, 20-27 X 40-60 p. 111. 



Page 109, after description of S. VARIANS, add, 



Var. MINOR Teodoresco, 1908, p. 188; Transeau, 1915, p. 23. 

 Cells 28-30/1 diam. ; spores 26-33 ft diam. Mass., 111. Europe. 



Var. SCKOBICULATA Stockmayer, fide Transeau, 1915. p. 23. 

 Spores scrobiculate. 111. 



Under S. COMMUNIS, cancel P. B.-A., No. 1416. 

 Under S. CONDBNSATA, add, The typical form occurs in Mass. 

 Page no, change S. DECIMINA var. SUBMARINA to S. SUB- 

 MARINA (Collins) Transeau, 1915, p. 25. 

 Under S. NITIDA. cancel P. B.-A., No. 513. 



