The nuclear components of the sex cells of four 
species of cockroaches. 
By 
Max Morse, 
College of the City of New-York. 
With 1 figure in the text and plates XXVI — XXVIII. 
The following article presents evidence for tlie conclusions, viz; 
1. Au unpaired idiochromosome or odd chromosome 1 ) is present 
iu the male of each of the species considered and the spermatogonia 
possess one chromosome fewer than the oögonia. 
2. In the spermatogonia, this odd chromosome is not cast out 
into the cytoplasm, as Moore and Robinson ('04) have stated (see 
page 2), but passes into half the spermatozoa, wliile a plasmosome 2 ), 
which stains with many chromatin dyes is extruded front the nucleus 
and this is probably the phenomenon which is described by the 
British writers. 
3. A side-by-side conjugation (parasynapsis, Wilson ’09) of the 
chromatin threads during synizesis probably occurs. 
4. Two longitudinal divisions of the chromosomes, tlius formed, 
take place in the two spermatocytes. 
5. Synizesis is not an artifact, but is a process bearing definite 
relations to the behavior of the centrosomes. 3 ) 
6. Rabl’s (’85) theory of individuality and Boveri’s (’04) '"Grund- 
gesetz der Zahlenkonstanz” are true as far as the persistence of the 
odd chromosome, from the beginning of the first spermatocyte stages, 
through to the formation of the Spermatozoon, affords evidence. 
v "Accessory chromosome”, Mc Clung; '"odd chromosome” or '"monosome”, 
Montgomery. 
2 j In the sense of Ogata (’83; , the first describer. 
3 j Hence corroborative of Schönfeld (’Ol), who first proposed the hypo- 
tliesis that synizesis was due to the attraction of the chromosomes by the 
centrosomes. 
