THE MEIOTIC PHENOMENA IN BLAPS 75 
whole, their number is fairly constant in every individual studied. 
I have failed in several attempts to arrange the small chromo- 
somes in pairs. In a few cases this could be done, but their 
small size prevents accurate measurements and comparisons. It 
is obvious that at least two or three pairs can be recognized, but 
it is very difficult to find such a pairing in the others. 
The two small chromosomes which enter the complex are not 
distinguishable from the others either in shape or size. Since 
the other thirty pair during synapsis, giving rise to fifteen bi- 
valents, it seems advisable to speak of them as the euchromosomes 
(McClung, ’14) in the description of the spermatocytes. 
During the resting condition of the spermatogonia the centro- 
some is placed somewhere between the nucleus and the mito- 
some or spindle remnant; this is specially seen when the cells 
assume a conical shape, the mitosome in this case being placed 
at the pointed end. Later on, during the prophase, the centro- 
some comes in contact with the nuclear membrane—if it was not 
before—and the astral rays are conspicuous at this time (fig. 13). 
The centrosome takes this position during the telophase or 
even at the beginning of this stage (fig. 31), moving along one of 
the sides of the nucleus. Figures 32 to 34 show some stages of 
this migration. In figure 32, upper cell, the centrosome, which 
since the late anaphase has two minute centrioles, still keeps its 
position in one of the poles of the already vanished spindle, but 
this position is unusual. In the lower cell of the same figure it 
is seen at the left of the nucleus. In figure 33 it is clearly detected 
in the lower cell, while in figure 34 it appears in both daughter 
cells. When the remnants of the spindle contract and condense 
to form the mitosome, the centrosome takes its final position 
(fig. 35) and upon elongation of the cell body usually loses all 
contact with the nuclear membrane. 
As a further proof supporting this account, it must be stated 
that in some spermatogonia in which the oval shape of the telo- 
phasic nucleus is retained, the free ends of the large chromo- 
somes, as seen in the prophase, are directed toward the centro- 
some (fig. 12); had not the latter moved around the nucleus, the 
conditions would be the reverse, with the apices of the loops nearer 
