ARCHER, ON SPIROTENIA. 187 
only the other day, in Reinsch’s lately published work on 
‘The Freshwater Alge of Franconia,™* it is stated by that 
writer—‘ The position of the Spirotenize in the system is 
still very uncertain; they belong, with Eremosphera, most 
probably to the Palmellacez.”? Again, in de Bary’s work on 
the Conjugate, as regards this genus, he states—‘“‘ On account 
of the fructification being unknown, the position of the entire 
genus is not quite certain.” + 
That this genus should be relegated to the Desmidiacez 
will, I think, be considered proven from the following de- 
scription of the conjugated state, as it differently presents 
itself in two distinct species, now for the first time recorded, 
and this notwithstanding Reinsch’s views expressed on the 
conjugation in Palmogleea,t a genus he still retains, notwith- 
standing de Bary’s beautiful researches.§ 
Before, however, proceeding to describe the conjugation of 
S. condensata, it would seem to me to be desirable to draw 
attention to the seemingly noteworthy fact that in this species 
the nucleus is parietal, not central. It forms a somewhat 
large elevation, rounded on one side and straight on the 
other, the convex side projecting into the cavity of the cell 
and gradually sloping off all round, and its flat side towards 
the wall; it is ordinarily placed equidistantly from either end 
of the Spirotenia. It has imbedded in the very centre a 
minute, light-coloured, distinctly marked nucleolus. The 
broad spiral band of endochrome, in making its revolutions, 
twice underlies the body of the nucleus, which fact will con- 
vey an idea of the extent of space covered by its flat side. 
The nucleolus always occupies a position just over the vacant 
interval between the two parts of the spiral. band which 
underlies the nucleus, thus the more readily disclosing itself 
to view, as there is there no chlorophyll-mass intervening to 
obscure or hide it. 
The figure described for the nucleus is, of course, that 
presented by it when seen from the side; when seen from 
above or below it naturally offers a rounded outline, and 
-might then be readily taken as a globular and central 
nucleus. 
It must be noted, however, that this characteristic of the 
nucleus is plainly to be seen only in specimens kept for some 
time in the house; in such examples the band of endochrome 
becomes much more sharply defined, with a smooth edge, like 
* ‘Die Algenflora des mittleren Theiles von Franken,’ p. 203. 
+ ‘Untersuchungen tiber die Familie der Conjugaten,’ p. 75. 
+ Reinsch, op. cit., p. 202. 
§ De Bary, op. cit., p. 30. 
