190 ARCHER, ON SPIROTANIA. 
inadequate and imperfect idea of the ultimate characteristics 
of these pretty and singular zygospores. On keeping the 
specimens it was found that they were not destined to re- 
main, like the zygospores of some species, absolutely smooth, 
and without external decoration. Presently there begins to 
arise what seems to be a kind of border of short linear spines, 
when an optical section, as it were, is brought into focus (fig. 8). 
But a more close examination shows that this is not a cover- 
ing of spines, but the beginning or basis of a honeycomb-like 
structure all over the surface of the zygospore, and the spine- 
like lines are merely the angles of the cells of the ‘ honey- 
comb” structure, a little thicker than their walls. By de- 
grees this honeycomb structure rises and enlarges; its cells 
become deeper and deeper; then the walls of the cells of the 
“honeycomb” become a little rounded externally, and each 
zygospore is complete (figs. 9, 10). 
By focussing an empty cell-wall of a zygospore, one can see 
down into the cavities or “‘cells”’ of the “honeycomb” structure 
at that part of the globe nearest to the observer, and by de- 
grees more and more obliquely as they pass round to the 
circumference, where they are, of course, as in the zygospore 
retaining its contents, seen sideways (fig. 11). By describing 
this remarkable structure as ‘‘ honeycombed,” I do not mean 
to infer that the cells, or cavities, or interspaces, are always 
hexagonal; they are, indeed, more or less irregular, being 
three, four, five, or six-sided. 
Thus, the conjugated state of this most marked species 
presents two noteworthy characteristics—one the doubly 
formed, as it were twin, zygospores; the other the remark- 
able “‘ honeycomb” structure externally decorating them. The 
doubly formed or twin zygospores have their parallel in a 
very few instances only, such as Closterium lineatum (Ehr.), 
and Closterium Ehrenbergii (Menegh.). In these the conju- 
gation of the parent pair of cells gives rise to two spores, not 
one only, as in by far the overwhelming majority of instances. 
But, though so far agreeing with the species mentioned, there 
are differences of detail, as is seen, proper to the species now 
in question. 
In the second circumstance, the “‘ honeycomb” structure, 
this plant is, so far as I know, absolutely unique. 
Indeed, these zygospores could not possibly in themselves 
be mistaken for any other unicellular vegetable form that I 
know of, if examined with any degree of attention. Viewed 
under a moderate power, there is just a possibility of the 
curious “‘asteridium”’ recorded by me, appertaining to Pe- 
nium digitus being confounded with it (fig. 4). The densely 
