128 
THE BREAKING OF THE SHROPSHIRE MERES. 
For several years I have gathered specimens of this species in 
the mere at Ellesmere, and kept them under observation for twelve 
months, with the result that I am able to state with confidence 
the formation of hormogonict at the base of the tricliomes, as 
observed in the genus Glceotrichia. My first observations were 
begun in 1881, the specimens having been gathered in August, 
shortly after the mere had broken, while as yet there were 
quantities of the alga forming a scum amongst the vegetation on 
the margin. My specimens were kept in a glass vessel in my room, 
and watched from time to time. The first change was the gradual 
decay of the extremities of the tricliomes, leaving about one third 
of their length green, and the disappearance of the basal heterocysts; 
at the same time, the gelatine of the frond became very much 
denser, and held more firmly together the surviving portions of the 
tricliomes, so that it was not easy to break them apart even when 
violently agitated. The cylindrical cell-walls of the tricliomes, though 
deprived of chlorophyll for a part of their length, still remained. In 
the course of time the lower portions of the tricliomes, destined 
to become hormogonia , from 40—60/*. by 6/*. broad, commenced 
to assume a deeper green - colour, being filled with coarse granular 
chlorophyll, and remaining enclosed in the exceedingly thin mem¬ 
branaceous sheaths, which projected some distance beyond their 
extremities. At length, with slight pressure under a covering 
glass of a microscopic slide, the hormogonia escaped from the outer 
sheath, having attained such a consistence as to keep their form 
unaltered. In another collection of specimens, obtained in 1885 
and kept under observation, exactly the same facts were seen, and 
about June of the following year the hormogonia commenced to 
form joints, some as many as nine. Owing, probably, to the 
conditions under which I kept them being unfavourable, I was not 
able to observe their further growth in July and August. I have 
now specimens gathered last year, with which I hope to be more 
successful in July. 
June, 1893. 
