50
III.
On the Occurrence of the Rhizopod, Clathrulina elegans,
Cienkowsky, in Essex.
By Charles Thomas, F.R.M.S., F.G.S.
Plate I.
[Read May 24th, 1884.]1
This beautiful member of the Heliozoan division of the
Rhizopoda is said to have been found in Wales and in
Ireland, but its occurrence in England has not hitherto been
noticed. It is illustrated in the 6th edition of Dr. Carpenter's
work on the Microscope, and is there described as possessing
"a soft sarode body, encased by a silicious capsule of
spherical form, regularly perforated with oval apertures, and
supported on a long silicified peduncle."
The specimens figured in the plate were found by myself
on the 16th of December, 1882, attached tp the decaying
part of the root of an old pollarded willow tree by the side of
a back-water of the Roding River, near Chigwell Lane,
Essex. The water was still, but not stagnant, as it is in
direct communication with the stream. The specimens have
been kept alive on a slide covered with thin glass until the
present time (January, 1883), and frequently observed.
When full grown the globular body is 0.1 mm. in diameter,
and it puts forth rays or radiating pseudopodia through the
circular or oval apertures in the capsule to the length of
fully 0.2 mm. from the circumference; these rays, however,
become shorter, and eventually disappear altogether as age
is attained. When in full vigour the rays appear instantly
1 [This short account of Mr. Thomas's observations is published in
advance of its order of date at the special request of the author. The
Editor feels greatly indebted to Mr. Thomas for the plate accompanying
the paper, engraved at his expense, by Messrs. West, Newman & Co.,
from his original drawings.—Ed.]