1909] ATKINSON—FUNGUS PARASITES OF ALGAE 337 
sphere), and finally dividing into the individual zoospores, the whole resembling a 
pandorina colony, but at last the zoospores separating. Zoospores reniform, 
laterally biciliate, 4-6 5—7 u 
n zygospores of S$ piri varians, S. insignis, and S. calospora, Ithaca, N. Y. 
Mycelio inequali, curvato, ramulo irregulare instructo, 3-84 lato. Zoospo- 
Tangiis irregularibus, saepe ramulosis. Ostiolo tubiformi tenuissimi aequali, 2 
lato. Prosporangiis ramulosis sectionibus mycelii formatis. Zoosporangiis 
vesiculosis, saepe deciduis, ciliis ornatis, ut coenobio Pandorinae natantibus, 
postremo divisis, zoospores formantibus. Zoosporis fabaeformibus, laterale 
biciliatis, 465-7 4. Hab. in zygosporis Spirogyrae, Ithaca, N. Y 
PHLYCTOCHYTRIUM PLANICORNE 
This genus, Phlyctochytrium Schroeter,*: differs from Rhizo- 
phidium in the presence of a swelling on the penetration tube, just 
inside the host cell wall, from which the delicate nutritive rhizoids 
grow. Phlyctochytrium planicorne has been found 
quite frequently in company with Lagenidium 
americanum, in the cells of Spirogyra varians, Be 
from the pool beyond Forest Home (near Ithaca). 
The zoosporangium is a little broader than long, 
measuring 68 m, and is broadest in the middle. 
At the apex it is provided with four plain dentate 
Processes around the exit pore. These dentate processes are char- 
acteristic of one section of the genus (Dentigera ROSEN,'? SCHROETER, 
0p. ¢., p. 79). The endophytic bladder-like base of the plant is 
separated from the epiphytic zoosporangium by a constricted portion 
at the point where the penetration tube passes through the cell 
wall of the host. This base is about 3 in diameter, and from 
it radiate several slender branching threadlike rhizoids. No zoo- 
Spores have as yet been observed. While it very frequent'y accom- 
panies Lagenidium, it is by no means confined to the cells affected 
by the fungus, being found on other cells also. 
Phlyctochytrium planicorne, n. sp.—Zoosporangium broadly elliptical, 
6X8 u, armed at the apex with four plain teeth. Endophytic vesicle globose, 
3H in diameter, with several radiating branched slender rhizoids. 
On cells of § he fo varians, often accompanying Lagenidium americanum, 
hear Ithaca, N. Y 
G. 7.—Phlycto- 
ee planicorne 
ene J., in ENGLER & PRANTL, Pflanzenfam. 11:78. 1892. 
*? Rosen, F., Ein Beitrag zur Kenntniss der Chytridiaceen. Beitr. Biol. Pflanzen 
45253-266. pls. 13, 14. 1887. 
