ULOTRICHES. 179 
The filaments are sometimes cylindrical, sometimes torulose like a 
rosary, in consequence of the barrel-like inflation of the separate cells; 
sometimes stretched out, sometimes frilled and interlacing each other, 
with a relatively thicker stratified membrane. Vegetative or asexual re- 
production is effected by macrozoospores, which originate 1-4 in a cell, 
and after becoming covered with a transparent bladder make their exit 
through an opening formed in the lateral wall of the mother-cell. The 
macrozoospores are of a thick, short, pear-shape, furnished with four 
cilia, a coloured spot, and w contractile vacuole. After a time they 
come to rest, and fixing themselves by the mouth end, they lose their 
cilia and envelope themselves ina membrane. The fixed end developes 
into a root-like, colourless organ of attachment; the free end growing 
into a club-shaped plantlet, through the cell, dividing into two by a cross 
partition, and each of these again in two, and so further. Sexual repro- 
duction arises through repeated bipartition .in each cell, from 8-32 and 
more, smaller microzoospores being produced. They have only two 
cilia, and after a swarming for a time they conjugate laterally in pairs, 
forming a zygospore, which attaches itself by the end corresponding to 
the mouth of the microzoospore. It grows very slowly, and finally 
breaks up by the simultaneous division of its plasma into 2-14 swarm- 
spores, which constitute the beginning of a new sexual generation. If 
any of the microzoospores remain behind in the mother cells, they are 
able, without copulation, to germinate and grow into independent plants 
which may be seen singly or in groups projecting from the mother- 
cells. 
Hormiscia moniliformis. (Kutz. Rabh. Alg. Eur. r1.,361. 
Pale green, more or less crispate, often mixed with other 
Alge ; cells equal or a Jittle shorter than their diameter ; cell- 
membrane thick, colourless, somewhat. lamellose, more or less 
constricted at the septa. 
Size. Cells 011-014 mm. diam. 
Ulothrix moniliformis, Kutz. Tab. Phy. ii, t. 88. Kirch. Alg. 
Schl. p. 76. 
In swamps, amongst Sphagnum, &c. 
Plate LXX. fig. 1. Portions of threads of Hormiscia moniliformis 
X 400 diam, 
Hormiscia zonata. (Web. § M.) Aresch. Obs, p. 12. 
More or less bright green, mucous, two or three feet long, 
often less, either floating or interwoven, sterile cells equal, or 
half their diameter; fructiferous cells usually a little longer 
than broad; cell-membrane thick, slightly constricted at the 
septa. 
eae Cells :012--04 mm. ; macrozoospores ‘012-018 x ‘01 
‘012 mm. ; microzoospores '005-"01 x ‘004-007 mm. 
Rabh. Alg. Eur. iii., 362. 
Ulothriz zonata, Kutz. Tab. Phy. ii, t. 90, f. 2. Kirch. Alg. 
Schl. p. 76. Dodel in Prings. Jahrb. t. x., pl. 1.-vi1. 
Lyngbya zonata, Hass. Alg. 220, t. 59, f. 1-6. 5 
oe 
