sob EIAS E Ae‏ ا کل سے الو عي يج eee ic ee‏ دو 
DEVELOPMENT 19 
more or less sunken, and the degree to which they develop within 
the substratum is very variable under natural conditions. The 
portion of the perithecium which develops below the surface is 
more or less covered with hairs which, on account of their de- 
velopment within the substratum, are seldom seen. In the dark, 
the perithecia assume a more superficial development and are com- 
pletely covered with these mycelial strands which assume the 
form of short wavy hairs, brown below and white toward their tips, 
giving the whole structure a grayish appearance. This hairy con- 
dition is sometimes met with in cultures made in the light, if a con- 
siderable amount of moisture be present so as to cause the de- 
velopment of perithecia on the glass at the edge of a thin film of 
moisture. It is, however, never so strikingly developed as in the 
dark. 
Cultures made on agar-agar fertilized with a very weak decoc- 
tion of horse manure, were inverted and placed in the light of an 
ordinary laboratory and in the dark respectively, darkness be- 
ing produced in this case by wrapping the culture dish in black 
cloth and placing it in a pasteboard box. The perithecia asumed 
an upright or oblique position, generally growing in either case 
with their beaks projecting into the agar; in fact, the perithecia 
were often completely buried. When mature, the spores were 
forced out in a small globular mass. Many of the perithecia, 
when examined after about three weeks, were found entirely 
empty. Nota spore could be found in them, showing that the 
process of ejection had been complete. In this case the agar was 
very transparent and the perithecia which were grown in the dark, 
especially, were so slightly colored as to readily reveal the out- 
line of any spores that might remain within them. The period of 
development was from two to three days longer in darkness than 
in the light. 
But little can be added to the oft-repeated accounts of the de- 
velopment of the perithecium. A constant watchfulness has been 
exercised to discover signs of sexuality but no conclusive results 
have been reached. The methods described for handling the 
mycelium intact on thin films of agar have given some fine prepa- 
rations of very young perithecia, and many structures similar to 
those which have been described as sexual organs, have been 
