192 DR LAUDER LINDSAY ON THE SPERMOGONES AND PYCNIDES 
spermogone, its body is almost in all cases a large white kernel of a dense horny 
tissue, which becomes gelatinous and semipellucid in water. From its density, 
it can easily be enucleated with the point of a needle, and I have already stated, 
that it sometimes falls out of itself. The diameter of this body is sometimes th 
to ;th. The envelope, which consists generally of a brown cellular tissue, is about 
ath to sth thick. The depth of the spermogone is generally as great, at least, 
as that of the thallus: and it may form, as in Hndocarpon, a slight prominence 
on the lower as well as on the upper surface of the thallus, where its depth 
exceeds that of the latter. The spermogones may either be scattered over the 
whole surface of the thallus, or only about its margins; or they may be confined 
to the plicze or rugee, with which the thallus is sometimes conspicuously marked. 
They are usually scattered over the general surface in S. dameecornis, obvoluta, 
carpoloma, and gilva; they are chiefly confined to the margins of the lobes in 
S. endochrysa, orgymea, glabra, and Freycinetii ; and they are scattered on the 
rugee or plicee only, or principally, in S. pallida, and linearis. But this distri- 
bution is by no means invariable; for, in the same species, the spermogones 
may be distributed sometimes in the one way, sometimes in the other. The sper- 
matia, in all cases, are straight and linear or rod-shaped, with obtuse ends; 
their length varies from sath to sath; their breadth, from sooth to za th. ‘The 
sterigmata are, in all cases, articulated and longish, bearing spermatia in great 
abundance on their sides and apices. They are composed of small, round 
or cubical cellules, at first having thin walls, which latterly become greatly 
thickened by deposits on their interior. They vary in length from jth to ath, 
with a breadth of from y,th to ath. 
Species 1. S. pulmonacea, Ach., 
Which has a very wide geographical range, occurring in Europe, Africa, America, 
and Australia. 4S. dinita, Ach., which occurs in Europe and Asia, is included, and 
very properly, I think by NyLANpER, asa variety. The spermogones are normally or 
generally here punctiform and depressed; but not always, as NyLANDER and KorBer 
describe them, for | have met with them occasionally, though rarely, papilleeform. 
The body of the spermogone is spherical; the cavity simple; the envelope re- 
sembles in structure the cortical layer of the thallus, being composed of very thick- 
walled cells. The internal tissue is whitish or pale rose-coloured; and, when dry, 
has a consistence as dense as horn; hence it is divisible by the knife into very 
thin sections. The body of the organ causes a slight protuberance or papilla on 
the under surface of the thallus. The horizontal diameter of the spermogone is 
about 5th to ;th; the thickness of its envelope jth to th. The sterigmata are 
very irregularly ramose and long, reaching almost to the centre of the sper- 
mogonal cavity. The constituent, short, roundish, or cubical cellules have a 
very narrow cavity from thickening of their walis in process of growth. The 


