Meek and ‘Worthen on Paleozoie Crinoidea. oT 
the Platyceras to grow within its reach to need its te size 
before devouring it? But if from some nown cause it 
should have done so, by what means could “ie Crinoid have 
nute organisms.* 
But we believe the strongest argument against the conclu- 
sion that the Crinoids, so frequently found with the shell of a 
Platyceras attached to them, died while in the act of sucking 
out, or otherwise extracting the softer parts of these mollusks, 
remains to be stated. In the first place, if such really was the 
nature of the relations between the Crinoid and the mollusk, 
it is of course self-evident that the continuation of the life of 
the latter must have necessarily been of very short duration 
on the contrary, in most if not all of these instances, the Pla- 
tyceras must have lived long enough in contact with the Crin- 
oid to have adapted the Bets id of the margins he ats shell 
f specimens of Platycrinus cpu and 
oidocrinus tuberosus, from Crawfordsville, Indiana, pile with 
a Platyceras attached, and in all cases where the specimens 
are not too much crushed or distorted, or the hard argillaceous 
y instances it m= clearly evident that it would have been an absolute 
y hand 
impossibility for penis t of our Carboniferous On oids to have han any 
dire aay to the only ope hrough the vault: that is, 
where this opening is s at the extremity of a straight rigid tube, often nearly twice 
the length of the arms, e th reme ends of their ultimate d 
are aware hse some have supposed this tube, or proboscis, to have been flexible, 
and the Messrs. Austin even thought it was especially designed and used for the 
paper of sucking out the softer parts of Polyps. If fle Eri we might suppose 
that in those cases where it was so much longer e arms, it could 
have bedi curved so as to bring its piety within aa of | the ends of the arms; 
but although we have in a few instances seen this tube more or less bent, a care- 
ful examination always showed that, where this was not due to an accidental 
and bent 
out of ten, if n re frequently, when not accidentally distorted, found 0 be 
perfectly diraigh, = a little inclined to one side or the riers 
