184 
ON THE PILOBOLID.E. 
matter having been projected by tlie same explosion to a 
height of forty miles in the atmosphere receives an important 
support, and the volcanic theory for the cause of the recent 
remarkable sunsets advocated in the former paper on the 
subject is further confirmed. 
ON THE PILOBOLIDiB, 
WITH A SYNOPSIS OF THE EUROPEAN SPECIES, AND A 
DESCRIPTION OF A NEW ONE. 
BY W. B. GROVE, B.A., 
HON. LIBRARIAN OF THE BIRMINGHAM NATURAL HISTORY AND MICROSCOPICAL 
SOCIETY. 
(Continued from page 153.) 
e. —The Spores. 
During this time the contents of the sporange have been 
resolving themselves into spores by free cell-formation. 
There are two modes of formation of spores which are some¬ 
times confused under this name :—Firstly, as in some species 
of Peziza, the cell-nucleus divides into two, then into four, 
and lastly into eight smaller nuclei, each of which surrounds 
itself with a portion of the protoplasm and constitutes a 
spore; secondly, as is described by De Bary in his account of 
tlie formation of the spores of Protomyces, the protoplasm 
may fall simultaneously into as many parts as there are to be 
spores, without the previous subdivision of a nucleus—in fact, 
the nucleus, if there has been one, disappears entirely as a 
preliminary of this process. There is a difficulty in observing 
the operation in Pilobolus, as, on account of the opacity 
of the membrane, the spores can only be seen by lightly 
pressing the sporange and observing those which protrude 
through the crack, with as little disturbance as possible. 
But after many trials I have come to the conclusion that the 
spores are formed in the following way. 
The contents of the sporange are mainly twofold, the proto¬ 
plasm proper, with the granules, and a hyaline homogeneous 
substance, the epiplasm. At the beginning these are 
thoroughly intermixed. The first stage in spore-formation 
is that the granules range themselves in short lines, which 
anastomose with one another, and form a regular “all-sided”* 
network, filling the whole interior of the sporange, its meshes 
being about the size of the future spores. The interstices 
* I.e., extending in three dimensions of space. 
