Pollen Mother-cells of Certain Plants . 
39 
Miyake (’05) found certain chromatic collections often present, but determined 
that they did not always correspond in numbers to the number of chromo- 
somes, and came to the conclusion that each chromosome was represented, 
not by a single chromatic mass, but by several such masses. Strasburger 
(’05) also found that similar chromatic collections were present in the 
somatic cells of Galtonia , and that there was an apparent correspondence 
in number to the chromosome number, a condition which did not obtain in 
Funkia. Tischler (’06) observed in Bryonia chromatic collections which 
varied in number and size, but came to no conclusion as to their relation to 
the chromosomes. The more deeply staining portions in the resting 
vegetative nuclei of Phaseolus and Solanum are regarded by Mano (’04) as 
portions of the chromosomes. Cardiff (’06) figures chromatic masses in 
resting meiotic nuclei which, however, do not correspond in number to the 
chromosome number. Noren (’07) also finds chromatic masses in Jnniperus, 
which are more numerous than the chromosomes. Kirwood (’07) finds that 
the chromatin during the early prophases of division in the pollen mother- 
cells of certain Cucurbitaceae becomes distributed in masses, which he 
regards as representing chromosomes. 
Prochromosomes, or bodies corresponding thereto, which bear some 
definite relation to the chromosomes either in number, form, or size, have 
been described for a rather large number of plants. We may summarize 
these results for convenience as follows: — Capsella bursa pastoris (Rosen- 
berg, ’04 ; Laibach, ’07) ; Zostera marina (Rosenberg, ’04) ; Calendula sp. 
(Rosenberg, ’04) ; Thalictrum purpurascens (Overton, ’05) ; Calycanthus 
floridus (Overton, ’05) ; Helleborus foetidus (Overton, ’05) ; Campanula 
grandis (Overton, ’05) ; Galtonia candicans (Miyake, ’05) ; Polysiphonia 
violacea (Yamanouchi, ’06); Hieracium auricitla (Rosenberg, ’07); PI. 
veiiosum (Rosenberg, ’07) ; Sisymbrium strictissimum (Laibach, ’07) ; 
Brassica Napus (Laibach, ’07) ; Stenophragma Thalianum (Laibach, ’07) ; 
Alyssum Wierzbikii (Laibach, ’07); A. argentum (Laibach, ’07); Iberis 
pinnata (Laibach, ’07) ; Lunaria biennis (Laibach, ’07) ; to which list we 
must now also add Richardia africana. 
Moore and Miss Embleton (’06) are thoroughly convinced that in 
somatic and pre-meiotic cells the chromosomes may be identified by 
chromatic rods or masses, which resemble chromosomes of division both in 
their number, form, and size. ‘ In Triton each anlage (or prochromosome) 
becomes gradually enlarged and thickened into a long pre-meiotic 
chromosome of the spirem figure, while in Periplaneta they gradually 
assume the form of dense, short rods characteristic of pre-meiotic division 
figures of that arthropod. In both cases the chief interest of these bodies 
lies in the fact that they obviously represent the chromosomes of division 
during rest ; and we may say without reserve that their presence at all 
stages of rest between the successive pre-meiotic divisions seems to con- 
