60 Indications of a Central Zone of Development 
“Flowever great,’ says Whitman quoting Gruber “the 
difference between an infusorian and a highly organized 
animal it cannot be a qualitative one. We can assume 
that the same vital elements serve in both as the founda- 
tion, only in ever new combinations. This kinship 
declares itself very clearly in the correspondence of many 
organs of the Infusoria with those of the higher or- 
ganisms. We mention only the membranellae of the 
Infusoria which are quite similar to the corner cells of 
the mollusk Cyclas cornea.” 34 : 
But we have already seen that when one cuts the 
infusorian into several nucleated fragments the membra- 
nellae can be formed from any given part of the proto- 
plasm of the original individual, and can be arranged in 
definite relation to one another under the influence of the 
nucleus as a center from which the formative activity of 
the entire organism radiates. It is then probable that the 
formation and manner of disposition of the corner cells 
of the mollusk Cyclas cornea may be due also to a similar 
process of centroepigenetic nature. But this justifies us 
in suspecting that in all pluricellular organisms whatso- 
ever, every formative process commencing with normal 
ontogeny is of centroepigenetic nature. 
This hypothesis is supported for example by the ex- 
periments of King upon regeneration in Asteria vulgaris. 
These have given among others the following results: 
each of the arms cut off close to the body can remain liv- 
ing by itself for two weeks but is incapable of regenerat- 
34Whitman: The Inadequacy of the Cell-Theory of Development. 
Biol. Lect. at the Mar. Biol. Lab. of Wood’s Holl, Summer Session 
1893; Boston U. S. A., Ginn, 1894. P. 118; and Journal of Morphol- 
ogy, Boston U. S. A. August 1893. Vol. VIII, No. 3, P. 651— 
652; Fig. 2 and 3. 
