1893.] Organism without Characteristics of Mother. 231 
results in this direction are on the whole not successful, and 
the explanation for this is to be found in the circumstance cited 
above, i. e., that the cross-fertilization between Echinus microtu- 
berculatus 3 and Sphxrechinus granularis 2 were scarcely ever 
successful out of 1000 cases. This small percentage of the 
whole number fertilized, where many millions of eggs or egg- 
fragments may be used, lends great improbability to the chance 
of getting successful results by isolating a few chosen examples 
of eggs. It is such a long and tiresome procedure to pick out 
and isolate the enucleated fragments from the shaken mass 
that in the limited time of my stay at the sea-shore I did 
not have the good fortune to see them develop in a single 
example. 
I hold as sufficiently strong proof, in absence of direct 
knowledge, the result of those experiments in bastardization 
where enucleated were mingled with nucleated fragments, and 
with entire eggs. For after I have been able to reach the con- 
clusion on the one hand by observing eggs and spermatozoa of 
the same species that enucleated pieces still develop, and on 
the other hand after it has been shown that the fertilization of 
nucleated eggs of Spherechinus with Echinus sperm larve 
occasionally arise standing between the parent forms, there 
remains no other interpretation as to the origin of the 
dwarf-larva of pure Echinus except out of the enucleated frag- 
ments found there. But there remains a more definite result 
pointing to the correctness of such a conclusion. One can dis- 
tinguish in a preserved and colored larva whether or not it has 
originated from a nucleated or enucleated egg, and this from 
the size of its nuclei. If the fertilized enucleated egg-fragment 
was the first segmentation nucleus which is formed entirely from 
A SPERM ATOZOON NUCLEUS, the nucleus is half as large asa normal 
first segmentation nucleus, and this difference in size is handed 
down to all of the descendants of the egg cell, even to the lar- 
Arg b Ree If now we B larvæ of the. same age derived 
ego-fi tilized by Echinus 
sperm, we have mixed together with the Bastard-type the true 
Echinus type, and the latter (true Echinus type) shows propor- 
tionately considerably smaller nuclei than the preceding one. 
