376 Report of the Microscopical Section. [Sess. 
There is not room here to give even a bare outline of more 
recent events—of the Tertiary volcanic outbursts, or of that 
interesting episode which I speak of as The Age of Snow. 
But it may be mentioned in conclusion that, associated with 
some of the remarkable Raised Beaches so well seen in Fife, 
there occurs here and there, close to Tyrie Bleach Works 
amongst others, traces of the boreal molluscan fauna which 
formerly peopled the Forth. 
REPORT OF THE MICROSCOPICAL SECTION. 
By Mr JAMES RUSSELL, Convener. 
In deciding upon subjects for session 1901-2 the Section 
wished to pursue the study of some typical forms of Animal 
and Vegetable Life. With this object in view the members 
resolved to adopt one or other of the excellent memoirs 
published under the auspices of the Liverpool Marine Biology 
Committee—known as “ L.M.B.C. Memoirs ”—as a text-book. 
The work of the session was accordingly commenced by the 
study of the Ascidia, treated of in Memoir I. 
According to Professor Herdman, Ascidians are now regarded 
as the degenerate descendants of a very lowly-developed group 
of the Chordata. Professor Garrod “considers them to be 
degenerated Vertebrata which should be placed quite at the 
end of that sub-kingdom.” The species studied was the 
Ascidia mentula, specimens of which were kindly procured 
for the Section from the marine station at Naples by Dr 
Davies. 
After the embryo Ascidia is hatched it leads for a day or 
two a free-swimming existence, and in this larval stage attains 
its highest degree of organisation, having developed along with 
other organs a notochord, thus claiming at this period to rank 
among the vertebrata. As, however, it approaches its adult 
state, a process of degeneration sets in. It attaches itself by 
its posterior end to some foreign body, such as a rock, a stone, 
or aseaweed. The tail, which formed its organ of locomotion, 
