State of Earth’s Interior. 17 
-ectosare of the parent, but remain for some time just outside of the 
latter, and apparently attached to it either by a sort of plasma or 
by short stalks. Fig. 4 | 
4th. The ERE develop cilia and swim away as free, ciliated 
embryos. Fig. 
5th. The Ea embryos become fixed to some object and 
acquire a triangular shape and a few (three or four) suctorial 
tentacles at each antero-lateral angle. At about this time the 
single anterior contractile vacuole appears. Fig. 6. 
6th. The animal now grows longer, and gradually acquires 
more suctorial tentacles until the adult form is reached. The 
develupment is illustrated in figs. 7, 8, 9, 10, 11, none of which 
are hypothetical, each having been observed by the writer. 
Fig. 2. represents an individual of nearly twice the ordinary 
length, showing two transverse constrictions or markings of the 
ectosare. In this, as in most other specimens examined, the 
animal is largely obscured by various objects, which seem to 
adhere to its surface as if it were covered by a viscid substance. 
AN INQUIRY INTO THE STATE OF EARTH’S 
INTERIOR. 
BY IRA SAYLEs.! 
HERE seems to be a strangely broad difference between the 
conclusions of the geologists and the physicists on the condi- 
tion of Earth’s interior. This broad difference, therefore, invites 
every thinker to think for himself, and to conclude as best he may 
be able. As a thinker I enter the lists. 
It is manifest, from a bare inspection of the question at issue, 
that it demands both the inductive and deductive processes of 
ratiocination. Inductively, the fact of heat must be established, 
its extent established, and its persistence established: deduc- 
tively must its maximum be reached, it effects be reached, and the 
main results of these effects be reached. 
1 U. S. Geological Survey. 
