23 
two species are they exactly alike, every separate part of their 
structure being subject to a large number of modifications, either 
of size, or colour, or else of arrangement. 
The border in some genera encloses nearly the whole of the 
internal organs, covering them over at the top, and leaving only a 
tiny pore by which the spores may escape into the external world. 
In others it is reduced to the smallest dimensions, and is thrown 
back out of sight by the growth of the internal parts. In the same 
way the basal tissue varies, now being thick and dense, now loose 
and thin. The filaments, the asci, the spores, in fine, every part, 
is subject to almost innumerable variations. 
But, of all the parts, none exceed the spores for variety of 
form and beauty of organization, Varying in size from the ten- 
thousandth to the eightieth part of an inch, in shape from a simple 
sphere to a long slender worm-like body, in colour from the utmost 
transparency to an almost inky black, and being, moreover, either 
_ simple or variously divided by internal partitions, they are objects 
of the most surprising beauty and delicacy. 
The first beginnings of the apothecium have been observed in 
very few Lichens, and only in very few instances has the part 
played by the spermatia been observed, and it is quite uncertain 
whether the apothecia of different families and tribes all arise in 
the same way. Stahl is the only one who has published details of 
its early development, and that only for species of Codlema. From 
his observations it would seem that the course of development is 
very like that which occurs in certain seaweeds, and quite different 
from what fungologists say takes place among the Fungi. I can 
confirm this so far, that after dissecting many apothecia in their 
very early stages I have never been able to see anything resembling 
the organs described for such plants as Ascobolus, Peziza, and 
others. 
I must now bring my necessarily brief account of these plants to 
anend. I should lke to speak more fully on several points than I 
have been able to do, especially on the internal structure of the 
apothecia and thallus, but limits imposed upon me by circumstances 
forbid. I can only add that I shall be extremely gratified if I have 
