114 BULLETIN: MUSEUM OF COMPARATIVE ZOOLOGY. 
Blackman (’05) found a plasmosome attached to the accessory chro- 
mosome of Scolopendra. A long list might be added to show that 
plasmosomes have been found associated with particular chromosomes. 
Many attempts, not altogether successful, have been made to explain 
the baffling relations to the other cell-structures of such bodies as have 
been called plasmosomes, nucleoli, chromoplasts, karyospheres, etc., 
but any future attempts to elucidate these relations must, I believe, 
be accompanied by a recognition of the relations that these structures 
bear to the organization of individual chromosomes. 
4. Persistence of chromosomes between mitoses. It still remains to 
discuss what may be the nature of the “ organization”’ of the chromo- 
somes in the stages through which the nuclear substance passes from 
one metakinesis to the next. I shall consider briefly (1) the origin of 
the nucleus from the chromosomes, and (2) theories of continuity. 
(1) Origin of the nucleus. In my description of the spermato- 
gonial divisions of Phrynotettix (p. 87-91), I pointed out that each 
chromosome becomes surrounded, as early as the anaphase, by a 
hyaline region, that this region expands in the telophase; that the 
chromatin of each chromosome becomes diffused to a certain extent 
within its own region; that a membrane becomes formed at the 
boundary between the hyaline region and the cytoplasm, producing 
the chromosomic “ vesicle’’; and that the nuclear membrane consists 
of the outer walls of the vesicles at the periphery of the nuclear group. 
I drew the conclusion that the hyaline region was formed at the ex- 
pense of the cytoplasm and that the material of each chromosome 
tended to remain within the space of its own vesicle, a core of chroma- 
tin being particularly noticeable in the center of this region, and that 
the prophase chromosome subsequently formed was developed out of 
the substance of one, and only one, of the previously existing telophase 
chromosomes. Sutton (’00) was the first to describe the vesicles of 
the spermatogonia of a grasshopper. Since then, Otte (’07) has seen 
similar structures in Locusta, and Davis (’08) in several Acrididae; 
Pinney (’08) has described them for Phrynotettix. Sutton stated 
that in the earlier stages of nuclear formation, each chromosome 
produced a separate vesicle, just as I have found for Phrynotettix, 
but that in later stages, the proximal ends fused together, giving a 
common nuclear cavity, from which the distal ends of the vesicles, 
particularly the longer ones, projected out like the fingers of a glove. 
Sutton interpreted these conditions as lending strong support to the 
theory of individuality. Otte believed that the individual vesicles 
remain distinct throughout the whole of the interkinetic phases, and 
