368 Kcuiffman . — A Contribution to the 
Hyphae rather slender ; zoosporangia nearly cylindrical. Oogonia with 
rather thick walls, terminal, intercalary or lateral, flask-shaped, rarely 
spherical, the lateral on short oogonial branches ; pits medium to large, 
rather numerous but not easily seen ; antheridial branches usually andro- 
gynous when the oogonium is lateral, diclinous when the oogonia are terminal 
or intercalary, long and slender when diclinous, short and slender and not 
coiled when androgynous ; antheridia on 75 per cent, to 90 per cent, of the 
oogonia, long, subcylindrical, not very profuse on a single oogonium, often 
only one present. Oospores up to 15 and 20 in an oogonium, average 
diameter 24 microns, with rather thick walls. 
The culture was obtained from ajar of Cladophora collected November 9, 
1905, in the Huron River at Ann Arbour. The final culture from a single 
zoospore was made January I, 1906. 
This form or one of its near relatives was studied by Klebs, and the 
results published in the paper which instigated this one. My own results on 
this form corroborate most of his essential observations, although the most 
attention was paid to the production of antheridia with inorganic salts. 
Cultures were made with solutions containing -05 per cent, leucin, and 
• i per cent, inorganic salts. The observations include the first nine days 
of growth : — 
(a) A 1 per cent, solution of leucin was first tried without any salts. 
Oogonia were abundant, and about 75 per cent, of them were provided with 
antheridia. 
(c) Leucin and potassium phosphate. Oogonial initials were formed, 
but did not develop into maturity; gemmae formed in considerable numbers. 
(d) Leucin and calcium nitrate. Oogonia fairly abundant ; about 
80 per cent, to 90 per cent, of them had antheridia ; oospores numerous up 
to 15 and 18. 
(e) Leucin and potassium nitrate. Oogonia abundant, antheridia on 
70 per cent, of the oogonia; oospores numerous up to 25. 
(/) Leucin and calcium phosphate. Oogonia abundant ; antheridia on 
90 per cent, or more, the oogonia densely covered by the antheridia in many 
cases; oospores not very well developed. 
( g ) Leucin and potassium'sulphate. Oogonial initials present ; antheridia 
not developed. 
(h) Leucin and sodium chloride. Oogonia fairly abundant, with 
antheridia on 80 per cent, of them ; oospores as many as 25 in each 
oogonium. 
(i) Leucin and magnesium sulphate. Antheridia on 95 per cent, or 
more of the oogonia; oospores 10--20 in each oogonium. 
Cultures with Na 2 HP 0 4 , (NH 4 ) 3 P 0 4 , NaH 2 P 0 4 , and NH 4 N 0 3 had no 
oogonia ; in the first three, gemmae formed in abundance. With ZnCl 2 in 
•1 per cent, solution death resulted. 
