Pollen Mother -cells of Certain Plants. 41 
come into view due to the chromatic substance flowing back along pre- 
determined paths into the primary chromosome bodies. 
The fact that the chromosomes persist as distinct bodies (the pro- 
chromosomes), suggests that they may have definite positions and attach- 
ments to each other as noted above. One of the first observations as to 
the organization of the cell related to the definite orientation of the 
chromosomes with reference to a ‘ polar field ’. I have not been able to 
find any connexion of the chromosomes with the cytoplasm, and it seems 
probable that such connexions are wanting, or much less definite in cells 
without centrosomes. Still Marquette (’ 07 , ’ 08 ), as noted, has observed in 
Equiseium and Marsilia that this synaptic contraction bears a definite 
relation in position to a mass of starch in the cytoplasm. A. and K. E. 
Schreiner (’ 05 , ’ 06 ), and Farmer and Moore (’ 05 ), and other zoologists have 
observed a certain definite relation between synapsis and the centrosome, 
and Harper (’ 05 ) has observed the same in the mildews. Synapsis may, 
perhaps, be an expression of one phase of the mechanics of division. 
Montgomery (’ 03 , ’ 04 ) has called attention to the polarity of the 
nucleus in Desmoganthus during synapsis, and a large number of figures of 
recent workers, especially among zoologists, which relate to the synaptic 
contraction, strongly support Rabl’s conception of polarity and permanence 
of the chromosomes. By an examination of the following figures one may 
observe that the chromatic threads converge thickly on the side of the nucleus 
on which the centrosome lies : see especially Eisen (’ 01 ), Batrachoseps , 
Figs. 12-15, PI. II ; Janssens (’ 01 ), Triton alpestris , Fig. 3, PI. I ; Triton 
punctatus , Fig. 32, PI. I, Figs. 49, 50, and 60, PI. II ; Janssens (’ 02 ), Text-figs. 
5, 8, 10, and 11 ; Schoenfeld (’02), Spermatogenesis in the bull, Figs. 3, 4, 
and 23 b, PI. I, which show a less distinct polarity ; Meves (’02), Palndina , 
Figs. 17, 18, and 19, PI. I ; A. and K. E. Schreiner (’ 04 ), Myxine, Text- 
figs. 2, 3, and 4, Spinax , Text-fig. 13 ; Farmer and Moore (’ 05 ), Periplaneta , 
Figs. 54-60 and 62, PI. XXXIX ; Figs. 68-72, PL XL ; Moore and 
Robinson (’ 05 ), Periplaneta , Figs. 9, 10, 11, and 14, PI. XLIV ; A. and 
K. E. Schreiner (’ 05 ), Myxine , Figs. 48-54, 56, and 59-66, PI. VIII ; 
Figs. 69-72, PL IX; Figs. 168-70, PL XIII ; Janssens (’ 05 ), Batrachoseps , 
Figs. 6, 7, 8, 14, and 15, PL III ; Fig. 36, PL IV ; Marechal (’ 05 ), Trigla 
hirundo , Text-figs. 3, 5, and 7 ; G aster os tens acideatns , Text-figs. 6 and 7 ; 
Amphioxns lanceolatas , Text-figs. 21-23; A. and K. E. Schreiner (’ 06 ), 
Tomopteris , Figs. 16-23, Pl. I ; Figs. 27-31, PL II, Salamandra , Figs. 8, 9, 
and 10, PI. XXIII; Figs. 32 and 34, Pl. XXIV; Spinax , Figs. 48-51 and 
53, PL XXIV ; P'ig. 56, Pl. XXV ; Myxine , Figs. 90-94, Pl. XXVI ; 
Marechal (’ 07 ), Pristiurus melanostomus , Figs. 8-12, PL I ; Scy Ilium canicula, 
Figs. 54, 56, and 57, PL III ; Gasterosteus aculeatus , Fig. 64, Pl. IV ; 
Van Molle (’ 07 ), Spermatogenesis in the squirrel, Figs. 6, 7, and 8, PL I ; 
Wassilieff (’ 07 ), Blatta germanica, Figs. 26-29, PL I, Figs. 30 and 31, PL II ; 
