Tort] SNOW—EPIPHYTIC ALGAE 367 
Aeronema, noy. gen.—Microscopic branched filamentous 
alga, filaments according to conditions often becoming beaded 
and fragmented or forming more or less parenchymatous masses. 
Chloroplasts several or many in each cell; light in color, without 
pyrenoid. Reproduction by means of amoeboid zoospores with 
a single flagellum, a single chloroplast, and a pigment spot. 
Found in Switzerland and the United States. 
Aeronema polymorpha, nov. sp.—Diameter of filaments 0.0028- 
0.006 mm. No starch or oil present; membrane (in beaded 
filaments) of cellulose; 16 or more zoospores formed in a cell, 
each 0.005-0.0065 mm. long and 0.0018-0.003 mm. broad. 
Found in Massachusetts. 
The writer wishes here to express her thanks to Miss F. G. 
SMITH for material brought from Guatemala, and to Professor G. 
Kress for guidance and inspiration in the oer study of these 
genera. 
MITH COLLEGE 
NortHAMPTon, Mass. 
LITERATURE CITED 
1. Cuopart, R., Extrait Bull. "Herb. Boissier. 11:no. 9. Sept. 1804. 
2. CreNKowsxr, L., Ueber Palmella Zustand bei Stigeoc lone Bot. Zeit. 
1876. 
3- Kiegs, G., Die Bedingungen der Fortpflanzung bei einigen Algen und 
Pilzen. Jena. 1806. 
4. Livincsron, B. E., On the nature of the stimulus which causes the change 
of form in Ragiagele green algae. Bor. GAZETTE 30:289-317. pls. 
17 78: 
5. LUTHER, ne Bikes till K. Sv. Vet.-Akad. Handl. 24:no. 13. 1899. 
6. West, G. S., A treatise on the British freshwater algae. Cambridge. 1904. 
EXPLANATION OF PLATE XVIII 
All rise ek fig. 16 were made with a Zeiss 3 mm. objective and no. 
6 ocular. Fig. 16 was made with a Zeiss 8 mm. objective and no. 6 ocular. 
An Abbé camera ie was used in all drawings except in fig. 18, when two 
of the zoospores were drawn free hand. 
Pirulus gemmata, nov. gen. 
Fic. 1.—Young cells. 
Fic. 2.—Mature cells. 
