DECEMBER 13, 1918] 
It was upon these branching filaments that 
the writer was astonished to see numerous 
struggling Stylonichia impaled, with the fila- 
ments passing through their bodies. Not the 
least astonishing was the fact that many of 
the animals were located at points basal to 
branches of the filaments, indicating that they 
had been held prisoner for some time. 
Fie. 1. 
The accompanying sketch (Fig. 1), drawn free 
hand at the time, indicates fairly accurately 
the conditions on one filament. A number of 
other filaments were observed to be similarly 
decorated. From the illustration it will be 
seen that, beyond the protozoon most proxi- 
mally placed on the filament, nine branches 
had arisen and beyond the most distal of the 
ciliates two branches had formed. Further, 
it will be observed that the animals invariably 
had their oral, or ventral, surfaces turned to- 
ward the base of the filament and that the 
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603 
filament passed through the oral aperture, or 
cytostome. 
Two ideas are suggested by these condi- 
tions; first, that the Stylonichia may have be- 
come impaled as a result of efforts to swallow 
the tip of the growing filament, and second 
that the growth of the filament was compara- 
tively rapid. Subsequent observations con- 
firmed these impressions. 
During the two hours following the dis- 
covery of the impaled animals some eight or 
ten individuals were seen to make the at- 
tempt to swallow the tip of one or another of 
the branches of the filaments. Stylonichia are 
known to be energetic feeders and, according 
to Stokes, this particular species is especially 
voracious, hence its specific name, vorar. In 
the observed instances the tip of a filament 
would be taken in until its extremity was near 
the posterior end of the animal. After a 
short time spent in the hopeless effort to de- 
vour the filament the ciliate would make an 
attempt to back away and divest itself of the 
unaccommodating object. In every case of 
this kind it appeared that the tip of the fila- 
ment adhered somewhat to the protoplasm of 
the protozoon, thus interfering greatly with its 
effort to release itself. There ensued there- 
fore a struggle upon the part of Stylonichia 
which, while possibly not describable as 
“frantic,” nevertheless gave evidence of tax- 
ing the powers of the animal to the utmost; 
and it gave rise to reactions which were de- 
cidedly opposed to the success of the object 
to be attained. To adopt anthropomorphic 
phraseology one might say that the animal, 
becoming desperate, seized upon anything at 
hand in an effort to pull itself away from the 
now offending “thorn in its flesh.” The 
most convenient and in fact usually the sole 
object offering such a possible means of escape 
was the filament itself. Consequently the ani- 
mal clung to the filament with its strong 
ventral cirri and endeavored in this way to 
pull itself away from the tip. The result was 
to pull itself still further on to the filament 
and thus to cause the tip to be thrust further 
into the protoplasm and even—as shown by 
