Frey—Physiology of Venturia Inequalis. 
315 
The third division is also a reducing division compensating for the 
vegetatve fusion in the ascus. The tetravalent chromosome num¬ 
ber before the first division in Otidea aurantia is four and follow¬ 
ing the first division each nucleus contains two chromosomes. In 
Peziza vesiculosa the first and second divisions constitute a 
“meiotic” phase. Eight chromosomes travel to the pole after the 
first division and on the spindle of the second, or homotypic divi¬ 
sion, four chromosomes appear and the resulting nucleus contains 
four chromosomes. Following the third, or ^ ‘ bracymeiotic ” divi¬ 
sion, the nucleus contains four chromosomes which are regarded as 
univalent. 
Fraser and Brooks (1909) hold that the first division in the ascus 
of Humaria granulata is synaptic and eight chromosomes migrate 
to each pole. In the second division four chromosomes appear and 
four migrate to each pole. The union of chromosomes takes place 
after the sexual, or pseudo-apogamous fusion in the ascogonium. 
The chromosomes of the asexual fusion, the fusion in the ascus, re¬ 
main apart until the heterotypic division is complete and then pair 
in the prophases of the homotypic, or second division, separating 
in the “ brachymeiotic ”, or third division in the ascus. Ascoholus 
furfuraceus is similar to Humaria granulata except that in the for¬ 
mer vacuoles play an important part in delimiting the spores. 
In Lachnea stercorea the nuclei fuse in pairs in the ascogonium 
and the chromosome number of the fusion nucleus is double that of 
the vegetative cell nucleus. In the second fusion in the ascus the 
chromosome number is doubled again making eight chromosomes in 
the primary ascus nucleus. The first division in the ascus is het¬ 
erotypic and four univalent chromosomes appear at each pole. The 
second division is homotypic and four chromosomes pass to each 
pole. During the prophases of the third division there are still 
four chromosomes. In the metaphase the four chromosomes are 
still present but they do not divide and two chromosomes pass to 
each pole. The third division is, therefore, brachymeiotic and dif¬ 
fers from meiosis in that there is seldom a synaptic contraction 
visible. When contraction does occur the reduced number of 
chromosomes is present in the prophase. If pairing occurs in the 
second prophase, reduction occurs in the second division. A sec¬ 
ond contraction never occurs during brachymeiosis. The absence 
of any pairing in the third division may indicate that the asexual 
fusions have little effect on the fungus. Perhaps the nuclei are 
too closely related. The spores are delimited after the manner 
