78 THE JOURNAL OF BOTANY 
narrowness of the cells. It occurred in large oon eh in one of 
the half-stagnant pools at the margin of a boggy spring. It was 
first noticed in April, 1912, and at this time I enorcah it must be 
gene yra, Mougeotia, and Vaucheria. Obviously these 
motile cells cota i in no way be connected with those Alge. In 
the spring months of 1913 the Chlamydomonas again occurred in 
great quantity in exactly the same place, and on this occasion the 
formation of daughter-cells was observed, the protoplast of the 
mother-cell dividing along a slightly oblique longitudinal plane. 
The chloroplast occupies all the median part of cg cell, and con- 
tains a small but conspicuous pyrenoid. There is a relat tively 
aes clear space at the anterior end of the cell ee a smaller one 
t the posterior end. 
XV.—OBSERVATIONS ON THE STRUCTURE AND LirE-HisToRY OF 
INIUM CALDARIORUM (Lagerh.) ges 
This Desmid was first described by Lagerheim* — t 
name of Mesotenium Endlicherianum Nag. var. Eo iiram, but 
y 
a correct one, since M. caldariorum appears to be a most character- 
istic species, the rather sudden attenuation of the extremities of 
the cells being a unique feature within the genus. There is also 
a faint and almost imperceptible narrowing of the median part o 
the cell. MM. enc ee is apparently a very rare Desmid. It 
is known from Sweden, Bohemia, and Kcuador, and there is up to 
now one British rout + Itis a subaérial species of the genus, and, 
so far, has been mostly found on the damp walls of green-houses. 
n traversing the Worcestershire area of the Wyre Forest in 
September, 1911, an extensive green stratum was observed under 
the surface of the surro ounding water, having all the appearance 
a Be hancilnee A . se dust on its surface. These individuals were 
way immersed in the water, but were living in a dam 
(probably saturated) atmosphere. 
oy << G. Lagerheim, Algologiska Bidrag. I., Botaniska Notiser, 1886, P- 48, 
xylogr. 
+ A. Hansgirg, Prodromus der Algenflora von Béhmen, Prag, 1888, p. 174. 
{+ W. & G. S. West in Bot. Trans. Yorks. Nat. Union, v., 1900, Da 42. 
