128 Hazen: NEW SPECIES OF LOBOMONAS 
ed about a week earlier in a much deeper pool, about half a mile 
distant from that just mentioned; this discovery was due to the 
fact that a fine colony of the Lobomonas developed on an agar 
plate containing a sample of my first collection of Pteromonas 
from this pool. The new species continued to appear sporadically 
in later gatherings from the same pool, the last being made 
November 12; it was also collected in October, together with 
Chlamydomonas metastigma Stein, from another rain-water pool 
in a wheel-rut, not far from the one first mentioned, though 
separated from it by railroad tracks bordered by a deep ditch 
on either side. The first mentioned wheel-rut yielded a few 
individuals in the following season. A few specimens of this 
species were also discovered during the past summer in a col- 
lection from a similar wheel-rut in northern Vermont: here it 
was accompanied by Gonium pectorale, Pandorina, Chlorogonium, 
Chlamydomonas, and a very interesting new form of Polyble- 
pharides, to be described in a forthcoming paper. The Lobomo- 
nas never appeared to be abundant like its associates in the 
same pools; usually not more than a dozen or two specimens 
turned up in one hanging drop mount. 
The vegetative cells or zoospores of this species most common- 
ly have a somewhat obpyriform shape (Fic. 22-27) though they 
are sometimes almost ellipsoid. In younger individuals the 
cell wall is so delicate and close-lying as to be indistinguishable 
for the most part, but in older cells it is well developed (FIGs. 
28, 29); it is generally produced into a variable number of lobes, of 
which from five to seven or sometimes as many as ten appear 
in a face view; that these lobes are developed on al) sides of the 
cell is clearly shown in a polar view (FIG. 30). At the anterior, 
usually broader end, the wall is extended into a truncate, wedge- 
shaped beak, or possibly more typically this takes the form of 
a more or less double papilla (Fic. 33); on account of the minute 
size of the organism it is often most difficult to see clearly the 
exact structure of this protuberance, which is one of the most 
characteristic features distinguishing this species from the two 
hitherto described in Europe. Sometimes the wall appears to 
be uniformly thin, sometimes thickened at the end of the lobes, 
and sometimes considerably thickened throughout. The proto- 
plast, indistinguishable outwardly from the bright green chro- 
matophore, fills the lobes in young individuals; in older cells it 
retracts more or less, so as to leave some or all of the lobes color- 
less. In such cases it is not easy to determine whether the 
