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



Var. COBRULEUM Transeau, 1915, p. 22. Median membrane 

 of spores steel-blue. 111. 



Under Z. INSIGNE, cancel, P. B.-A., No. 457. 

 Page 103, cancel var. DECUSSATUM. 

 Page 105, after first three lines, add, 



9. Z. DECUSSATUM (Vauch.) Agardh', 1817, p. XXXII; 

 Transeau, 1914, p. 290; Z. pectinatum var. decussatum Collins, 

 1909, p. 103 ; Conjugata dccussata Vaucher, 1803, p. 76, PI. \ II, 

 fig. 3. Vegetative cells 18-20 /* diam., cells 3-5 diam. long, mem- 

 brane not specially thickened ; spores 27-30 /i diam. Mass., 

 Ill: Europe. 



10. Z. PELIOSPORUM Wittrock, 1868, p. 188 ; Transeau, 

 1915, p. 21. Vegetative cells 24 p. diam., 1-3 diam. long; fer- 

 tile cells swollen on the inner side ; spores subglobose, 33 /* 

 diam., dark blue, median membrane scrobiculate. Cal., Colo., 

 Vancouver. Europe. 



P. B.-A., No. 808 ; Tilden, Amer. Algae, Nos. 156, 392, all 

 distributed as '/.. chalybtospermum, belong to this species. 

 There seems to be no certain record for /.. chalybcosperntum in 

 this country. 



11. Z. CYLINDRICUM Transeau, 1915, p. 22. Vegetative 

 cells 28-33 /* diam., 1-2 diam. long ; zygospores unknown ; 

 aplanospores cylindric or tumid-cylindric, filling the cell, 

 30-33 X 24-58 ft, median membrane brown, scrobiculate. 111. 



12. Z. RHYNCHONEMA Hansgirg. i888a, p. 257; Transeau, 

 1915, p. 22. Vegetative cells usually 12/1, sometimes 16-20/1 

 diam., cells 2-6 diam. long; conjugation always lateral, spores 

 subglobose, about 33 /* diam. 



The dimensions given above are for the European, typical, 

 form ; the specimens from Vancouver, attributed to this species, 

 have cells 22-28/4 diam., 1-2 diam. long; the zygospores are 

 ovoid, 24-28 X 36-44 p., and the conjugation took place through 

 the partition wall. Aplanospores also occurred, globose, 24-26 

 n diam. 



13. Z. COLLINSIANUM Transeau, 1914, p. 289, PI. XXV, 

 figs. 1-3. Vegetative cells 18-24 M diam., 2-3 diam. long, fertile 

 cells swollen on the inner side ; zygospores globose, 26-40 /* 

 diam., or oblong. 26-40 X 30-47 /*. median membrane blue, 

 with large pits; aplanospores cylindrical-oblong, 18-24 X 

 40-76 M. scattered among the vegetative cells, color and mark- 

 ings as in the zygospores. III. 



