81 
200, 210, 220, 223, 250, 280, 280, 300,300, 300, 310, 315, 320, 325, 
340, and 350 u. 
The maturation period for the cysts is from 4 to 6 days in water. 
Throughout the period of maturation each cyst was observed to pass 
through a regular series of changes. This cycle may be followed in the 
changes of a cyst collected on July 18 and kept in water. During the 
first thirty hours in water the cyst proper become lighter and less dense 
in a peripheral zone which extended into the cyst for about one-eighth 
of its diameter. This less dense zone was rather uniformly filled with 
fine granulations while the central mass was even more dense than when 
the cyst was first discharged, as if the more dense material had simply 
concentrated in the center. Toward the close of the second day four 
buds appeared on the central mass. These were symmetrically arranged 
about 30 degrees from an imaginary pole. These four buds pushed out 
into the less dense peripheral zone of the cyst and shaped themselves 
into sporoducts. The distal end of each sporoduct-bud contained a 
shallow depression while a narrow flange was elevated around the proxi- 
mal portion near its junction with the main spore mass. By the end of 
the third day these sporoduct-buds were well developed and quite pro- 
minent. Meanwhile changes had taken place in the central mass of the 
cyst. The more dense material had settled back to the pole opposite 
that surrounded by the sporoduct-buds, extending up into the center of 
the cyst as a conical mass, while the less dense material rested on top 
of the more dense just below the sporoduct-buds, (see fig. 4). Dehiscence 
took place late in the fourth day. 
The everted sporoducts were extremely long when compared with 
the size of the cyst and their own diameter. They varied in length from 
3000 u to 3500 u, (3 to 3.5 mm.), and with one exception were always 
four in number. One cyst which was apparently the same as the rest 
produced five sporoducts. The sporoducts were of uniform diameter, 
being about 10 x in width excepting at their junctions with the spore 
mass where they widened to 14 u. The envelopes of the cyst seemed to 
suffer very little from the dehiscence, although the outer was pushed out 
somewhat around the sporoducts in the regions they passed through. 
Cysts from which all of the spores had been discharged showed the inner 
envelope to have thickened internally to about twice its original thick- 
ness around a small gray residual mass, suggesting that the compression 
of the spore mass by this internal thickening supplied the power by 
which the spores were expelled. 
Spores. The spores were discharged in chains and were united 
when they left the sporoduct. The chains however broke up very soon 
after they were expelled from the sporoduct so that the individual spores 
Zoolog. Anzeiger. Bd. XLIII. 6 
