CHROMIDIA AND THE BINUCLEARITY HYPOTHESES. 3803 
accepted by Boveri (00), in whose laboratory the observa- 
tions were made. 
Ancel (02) has given a most exhaustive account of the 
same structures. He believed that the pseudochromosomes 
and Nebenkern were stages in the development of the same 
thing, but that they were not formed from nuclear chromatin, 
being “the product of transformation of differentiated cyto- 
plastic filaments.” 
Bolles Lee (02) says the Nebenkern in Helix is nothing 
but a degenerating bunch of spindle rays. He ‘can affirm 
that the Nebenkern is derived from the spindle with as 
much certainty as one can affirm that an oak is derived from 
an acorn.” 
““ chromidia” of 
In face of these assertions regarding the 
Helix it is surely necessary for Popoff to bring some further 
proofs forward before we can accept his interpretation.’ 
Attempts have been made to homologize various structures 
(mitochondria, etc.) in nerve-cells with chromidia, (e. g. by 
Goldschmidt, ’04a; Popoff, ?06, etc.) But the evidence is 
even less convincing than in the two cases already given. It 
seems not unlikely that they, lke the “chromidia”’ of 
Ascaris and Helix, are really nothing more than the remains 
of centroplasmic fibres. It is significant that this same result 
should have been-arrived at in these different cases by quite 
independent observers. 
Chromidia have been described in several other multi- 
cellular organisms, e.g. in dicyemids (Hartmann, ’07). They 
are here said to play a part in the vegetative life of the 
animal, but the observations require confirmation. And this, 
indeed, may be said of most cases of chromidia in the 
Metazoa.? 
1 According to Wassilieff (07) similar structures (mitochondria) in 
the spermatocytes of Blatta germanica originate from the nucleus, 
but are “no special kind of chromatin, but only superfluous chromatin.” 
? An interesting chromidial condition appears to occur also in sponges, 
e. g. in the gastral actinoblasts of Clathrina cerebrum, as described 
by Minchin (98). I am indebted to Prof. Minchin for kindly calling 
my attention to the fact. 
