256 
PROCEEDINGS OP SOCIETIES. 
this state a withdrawal of the endochrome, leaving a little clear space at 
the ends, of a somewhat triangular outline, as if hounded on two sides by 
the outer wall, and in which there is sometimes to he seen a detached 
granule; hut I am not able to make out that this moves. But even in 
this altered state of S. ohscura (as in Scenedesmus), its oblique mode of 
division, and consequent unsymmetrical outline, will easily distinguish 
it from the form under consideration. 
Indeed, this form to me appears very distinct from any other de¬ 
scribed, and though I have contrasted it with others (almost unnecessarily 
in some cases), a moment’ s inspection of recent specimens would, I think, 
on this point convince any observer. I shall, then, describe this species 
as follows:— 
Penium Berginii {n. s.) 
Frond minute, about three or four times longer than broad, smooth, 
fusiform; segments cuneate; ends roundly pointed; endochrome irregular, 
or sometimes with more or less evident longitudinal fillets, also with a 
transverse pale band, and having close to each end of the frond a con¬ 
spicuous, well-defined circular cavity, containing moving granules, and 
each half usually having immersed in the rest of the endochrome a single 
central spherical corpuscle. 
Length of frond, 4 I 0 to 5 I 0 of an inch; greatest breadth, ttVo of an 
inch; diameter at the ends, Ttko of an inch. 
I feel very happy in being accorded the privilege of naming this spe¬ 
cies after the well-known microscopist, Thomas F. Bergin, Esq., M.B.I.A., 
President of the late Microscopical Society of Dublin; while I trust that 
gentleman may look upon this trifling compliment as a mark of unaf¬ 
fected, but sincere, respect for his numerous scientific attainments, and 
more especially in regard to microscopy, the active pursuit of which has 
been interrupted owing to delicate health, at once greatly to be la¬ 
mented for his own sake, as well as much to be regretted for the cause 
of science. 
I have thus endeavoured to give my own ideas as to the various new 
forms, or other matters to which I have directed attention. In regard 
to my new filamentous form there can be no doubt that it is a Desmid, 
and as I could not satisfactorily to myself refer it to any genus described, 
I had hence no alternative but to attempt to make a new genus to 
contain it. Considering the note appended to the record of the occurrence 
of Bocidium asperum (Brel .) in my former catalogue, it may appear un¬ 
justifiable temerity on the part of an amateur to essay that, which I 
there expressed a hope that the occasion might arrive when some of our 
u master-hands” might see it advisable to accomplish. I had not at that 
time met with Leptocystinema Kinahani —the impression then upon my 
mind had grown into a conviction, so far as my own judgment on the 
matter was concerned—and so (though unaided by the advice or opinion 
of any fellow amateur making these organisms a study, but which I had 
