124 Hazen: NEW SPECIES OF LOBOMONAS 
is probable that Lobomonas has escaped the notice of collectors 
to some extent because of the minute size of the cells, but doubt- 
less it is actually one of the rarest genera of the Chlamydomonas 
group. The two new species now presented serve to emphasize 
the unity and distinctness of the genus, and also provide certain 
features of division and conjugation not known hitherto, which 
indicate a fundamental parallelism with Chlamydomonas. 
Lobomonas pentagonia sp. nov. 
This species, the first of the genus to be reported in England, 
I believe, was discovered in considerable abundance, together 
with two species of Pteromonas, at Ham Common, Surrey, near 
Kew, in 1920. The habitat was the border of a small shallow 
pond at the west end of the common, a place frequented by cows 
and horses, and therefore supplied with water containing a 
considerable amount of nitrogenous organic matter in solution: 
in fact the general conditions were very like those of the much 
smaller pool where Lobomonas rostrata, to be described presently, 
was found with another species of Pteromonas in New Jersey. 
Like all other species of the genus, L. peniagonia is very 
minute, but it is more constant in form than L. Francei or L. 
rostrata. When seen in side view the cell appears rather pent- 
agonal in outline (Fics. 1-4), but careful focussing shows that 
the angles do not all lie in the same plane. Polar views often 
show five to eight protuberances (Fic. 14), likewise not all at 
the same level. One of the most symmetrical specimens, when 
resting with its ciliated end turned upward, shows four anterior 
protuberances and, alternating with them, four others at the 
posterior end of the zoospore (FIG. 5); the number, however, is 
variable. The protoplast, including the chromatophore, in 
young individuals usually extends into and fills the protuber- 
ances, and ends anteriorly in a somewhat obtuse beak, to which 
the two cilia are attached (Fic. 1). In older specimens the pro- 
toplast usually retracts from one or more of the wall protuberances 
and leaves them empty: they do not appear like dense gelatinous 
structures. The chromatophore is more or less hollowed out 
in the common Chlamydomonas fashion but thickened in the 
region where the pyrenoid lies in a somewhat lateral position. 
The two alternately pulsating vacuoles lie in a plane nearly 
perpendicular to that passing through the two extended cilia 
(Fic. 5), as in most species of Chlamydomonas, so that in the 
ordinary face view of the cell only one is usually seen. The 
