ON SH£PHEARDELLA_, A NEW TYPE OF MARINE RHIZOPODA, 133 
On the 12th of March last I noticed a fine Shepheardella 
entangled among the tentacles of a Hydratuba,” and 
placed it between two thin cover-glasses for examination 
with higher powers^ care being taken not to press it. Urti- 
cating threads of the lasso-cells had pierced the integument 
of the rhizopod in many parts_, but did not seem to cause 
any inconvenience. The nucleus was finely developed, and 
was watched most closely, in order to determine, if possible, 
whether its movements were the same, or an effect of the 
rotation of the sarcode. These movements proved, however, 
more puzzling and erratic than ever, the difficulty being 
increased by the density of the sarcode. Finding that no 
satisfactory results could be obtained otherwise, I subjected 
the creature to sufficient gentle pressure to force out most of 
the sarcode, when I had the satisfaction of observing that 
the nucleus continued its meandering course, somewhat after 
the fashion of a large Paramaecium, for about half an hour 
after all motion had ceased in the sarcode which surrounded 
it. The rotation of the sarcode was at once interrupted and 
speedily stopped altogether by the pressure applied ; the 
nucleus gradually ceased to move to and fro in about thirty 
minutes afterwards, a few signs of life being exhibited by 
its protoplasmic contents for a few minutes longer. The 
nucleus membrane was deeply contricted and wrinkled into 
a constantly varying series of elevations and depressions, 
forming avenues, through which the granular sarcode passed, 
and at times appeared to receive increased impetus in doing 
so. In consequence of these ever-changing appearances the 
various parts of the nucleus could only be distinguished 
from each other at rare intervals. Sufficient, however, had 
been seen to prove that the nucleus possesses the power of 
independent movement, but probably not in so high a degree 
as the sarcode, in the more powerful stream of which it is, 
as already stated, carried along with irresistible force. 
With two exceptions the specimens of Shepheardella exam- 
ined have each possessed one nucleus. One of the ex- 
ceptional specimens was rather small and pale coloured, and 
contained no visible nucleus ; the other was of full size and 
colour, and possessed three nuclei, all of which were of full 
size and exhibited the same phenomena of moving lines. 
They were carried along independently in the sarcode stream, 
sometimes coming into collision and becoming blocked for a 
short time, and then forced on again with a jerk by the col- 
lected force of the choked current. 
This particular specimen was first observed on the side of 
a bottle, to which it adhered so firmly by its extended pseu- 
