1906] OVERTON—THECOTHEUS PELLETIERI 473 
the surrounding epiplasm, perhaps slightly more dense and gran- 
ular. No particular granular area is present. It is simply a portion 
carved out of the homogeneous cytoplasm in which the nucleus is 
situated by means of a delimiting kinoplasmic membrane. In jigs. 
12a-12¢ slightly older spores are shown. They are arranged in the 
form of a hollow cylinder around the wall of the ascus. About five 
young spores are arranged vertically along the ascus walls in any one 
plane. Fig. r2a represents a median longitudinal section of the ascus; 
jigs. 12a and 120 are slices off the same ascus. 
BARKER (:03) found that the numerous nuclei in the asci of 
Ryparobius became arranged in the form of a hollow sphere just 
beneath the wall of the ascus before spore delimitation. Each asco- 
spore when completely formed, therefore, has one end toward the 
center and the other toward the ascus wall, the resulting arrange- 
ment of the spores thus being radial. In Thecotheus the nuclei, as 
noted above, are not arranged radially, but in the form of a hollow 
cylinder about the wall of the ascus, in a denser peripheral layer 
of the epiplasm. The resulting spores, therefore, have their long 
axes parallel to the wall of the ascus. In this respect Ryparobius 
and Thecotheus are essentially different. Due to this peripheral 
arrangement into a hollow cylinder, the spores are forced to occupy 
considerable space in the ascus, some being pushed up near the tip. 
The epiplasm is at this time everywhere much more vacuolated than 
in earlier stages, and the ascus is exceedingly turgid and swollen 
(figs. 12a-12¢.) 
In jig. 12a the spores can be seen to show no sign of an exospore 
or endospore. DEBary (’63, ’64) thought that the exospore was laid 
down upon the surface of the spore from the epiplasm, which explana- 
_ tion seems to have gained rather widespread acceptance. The exact 
method of exospore formation needs investigation. FAULL (:05) be- 
lieves that two membranes are formed, one beiag the plasma-membrane 
of the spore and another formed concurrently with this, which lines 
the cavity in which the spore is to lie. These membranes occupy the 
positioa of the hyaline zone described above. The spore wall is sup- 
posed to be laid down between the membrane bounding the epiplasm 
and the plasma membrane of the spore. Fautt suggests that both 
membranes are perhaps active in the formation of the spore coats. 
