FAULT: DEVELOPMENT OF ASCUS. 
81 
though much lighter in color, and were protected by a hirsute cov¬ 
ering. Some had attained a height of 2 cm., and a diameter of 0.6 
cm. Several were marked, and placed under further observation. 
It was found that they matured rather slowly in the spring, for 
they were not ready to shed their spores until the early part of May. 
Several fixing fluids were used, but Flemming’s weaker solution 
was found to be the most satisfactory. Likewise several stains were 
tried, but Flemming’s triple stain of saffranin, gentian violet, and 
orange G, and Haidenhain’s iron-haematoxylin were found to be 
superior to all others. 1STo hard and fast rule can be laid down for 
staining. Nearly every species requires a somewhat special treat¬ 
ment. Material for cutting was embedded in paraffin whose melting 
point was about 57° C. and sections were cut from 3 p, to 5 /j. in 
thickness. In determining the origin of the ascus it was frequently 
of advantage to crush slices of fresh or preserved material, prefer¬ 
ably the latter, and examine in water or potash. Figures 70 to 80 
(pi. 11) were drawn from preparations made in this way. 
Hydnobolites sp. 
Within the bounds of a brief paragraph, Errera (’ 82 ) recorded 
the fact that the spores of Tuber are formed simultaneously and not 
successively, as was formerly believed, that at the moment of their 
birth they are surrounded by a thin membrane, and that the rest 
of the protoplasm in the ascus condenses about them to form the 
greater part of the exospore. Berlese (’ 99 ) has recently given us a 
much fuller and more accurate account of the phenomena that occur 
within the ascus of Tuber brumale. Hydnobolites as far as I am 
aware is the only other hypogeous Ascomycete that has been exam¬ 
ined from a modern cytological standpoint. I owe the material to 
the kindness of Professor Thaxter, who gathered it at Kittery Point, 
Maine, in September, 1903. 
Hydnobolites is admirably adapted to a cytological study. The 
fruits can be readily cut into thin sections, and each section contains 
two or three score of asci in all stages of development. The asci 
are comparatively large, and owing to their spherical shape and the 
disposition of the spore-forming plasm do not suffer from being cut 
in any plane. Tuber dryophyllum was also examined, but not as 
fully, for its structural features are on a smaller scale. There is 
