are explained by Geometry. 7 
still, so long as they remain in their matrix, they are devel- 
oped in forms far more rounded than those which they imme- 
diately assume on changing their medium and coming out into 
the world. From the simplest entozoa (Ascaris acuminata) to 
the chick in ovo and mammalian embryos (foetus in utero, &c.), 
this fact is illustrated. To the same category also there obvi- 
ously belong those orgasms which, though not produced within 
the parent tissue, are yet retained in such union with it that 
the deployment of individual life in them is prevented. Such 
are gems, buds, tubers, &c. And of these itis not to be denied 
that the sphere is the typical form. And so in other cases. 
Here also the entozoa present themselves. They exist in a 
medium too similar to themselves to admit of a full development 
of life and of those expanded organs which, as we shall after- 
wards see, places a living creature in harmony with a favour- 
able medium. Now, though it may be said that the entozoa 
tend to form an animal kingdom of themselves, and, as far as 
is possible, to represent all forms in the animal kingdom, yet 
they are very unsuccessful. In so far as they are truly 
simple, and neither compressed nor lengthened by currents 
plying along the walls to which they are attached, they tend 
to be eminently spheroidal (Acephalocystis, Gregarina, &.), 
usually giving, as a departure from the spherical, only such 
head and neck as are necessary to secure their position (Kch- 
inococcus, Cysticercus, &c.) But among such animals there 
ig no reason why their simple forms may not be repeated in 
continuity in the position in which one individual has suc- 
ceeded in establishing itself, so as thus to give species of a 
higher order to nature, species composed of self-repeating 
parts either loosely jointed (tape-worms, &c.), or compactly 
annulated and unified (ascarides, &c.). 
As to those conditions of existence in which the difference 
between the orgasm and its ambient medium is too great’for 
the deployment of life, while yet it is not so great as to dissolve 
or destroy the orgasm, they are manifold, but they always 
sanction the same principle of morphology ; they always give 
_ the spherical as the typical form of the orgasm or living being 
so situate. Such a living being may venture out perhaps, and 
even show a tail (Amaroucium proliferum), or it may try a 
