130 ERYTHEA. 
to the ones which I have called zoospores as occurring in 
Spirogyra crassa. Their mode of formation was different 
from what I have noted. Mr. Carter states that after coming 
to rest the spores become brown and finally break up into 
colorless monads. He concludes that this is the origin of 
the animal rhizopod, Actinophrys. 
A paragraph from Braun’s ‘‘ Rejuvenescence ” quoted in 
Cooke’s Fresh Water Algae, p. 152, states that these swarm- 
ing cells of spirogyra differ from normal swarming cells “in 
their irregular form, slower motion, varying size, and mostly 
brownish yellow contents which become hyaline finely gran- 
ular mucilage.” 
An account published in the Micrographical Dictionary, p. 
715, is as follows: 
“Tn filaments in an unhealthy condition, about to decay, 
such as are often seen when a collection of them is placed in 
a jar of water to keep for examination, it is not uncommon to 
see the green contents gradually lose their spiral arrangement 
and break up into a number of globular portions; we have 
sometimes observed these rolling over slowly in the cell. In 
one case we have seen the contents converted into sixteen 
distinctly organized biciliated zoospores differing only from 
the ordinary zoospores of the confervoids in the almost total 
absence of color. They were somewhat crowded in the cell 
and moved lazily about in it, the cilia vibrating.” 
This last description comes nearer to my own than the 
others. My specimens, however, appeared to be in a healthy 
condition, and the zoospores were more numerous and more 
active at the time of collecting. After they had been kept in 
water a few days, the zoospores did not form. Still the fila- 
ments disintegrated more rapidly than in any other speci- 
mens of Spirogyra which I have kept for examination under 
apparently the same conditions of environment. 
It seems probable that weakness or disease tends to the 
formation of zoospores in Spirogyra, but the detailed history 
and full significance of these bodies are matters for further 
investigation. 
