282 G. CARL HUBER 
was necessary to reduce proportionately the thickness of the 
wax plate representing them. Asa rule, these were made about 
one-half the thickness of the other plates. The irregularities 
revealed by the rough model after superimposing the respective 
plates, not so marked as might be supposed considering the 
thickness of the plates used, were adjusted, not by trimming 
the model and cutting away wax, but by smoothing with warm 
irons. The possibility of error is admitted, but since all of the 
models were made in the same way, errors if committed were 
probably essentially the same for all of the models. The volumes 
of the models were obtained by weighing the water displaced 
by each, and after making the necessary temperature corrections, 
reducing weight of water displaced to volume. The average 
of several determinations is given in table 4. 
TABLE 4 
ACTUAL VOL. AVERAGE VOL, 
RECORD NUMBER AGE STAGE OF EGG MASS PER STAGE GIVEN 
IN C. MM. IN C. MM. 
106 1 day pronuclear 0 .00015058 
106 1 day pronuclear 0 00014317 
106 1 day pronuclear 0 00015775 
106 1 day pronuclear 0 .00017127 0 000155693 
59 2 days 2-cell stage 0 .00016240 
59 2 days 2-cell stage 0.00018273 0000172565 
50 3 days, lhr.| 4-cell stage 0 .00018338 
50 3 days, lhr.| 4-cell stage 0 ..00015520 0..000162443 
57 3 days, 17 hrs.| 8-cell stage 0 .00018893 
57 3 days, 17 hrs.| 8-cell stage 0 .00016040 
57 3 days, 17 hrs.| 8-cell stage 0 00018653 
57 3 days, 17 hrs.| 8-cell stage 0 .00018193 
57 3 days, 17 hrs.| 8-cell stage 0 .00019979 0 .000183516 
57 3 days, 17 hrs.| 11-cell stage 0 .00021025 0 .00021025 
The uniformity of the figures giving the actual volume of the 
ege mass, as determined by the weight of the water displaced 
by the models of the respective ova reconstructed, leads me to 
feel that the errors committed in reconstruction were not serious. 
The last column of the table, giving averages, is of interest 
since it shows a very slight increase in the volume of the egg 
mass during segmentation and transit through the oviduct. 
Following the pronuclear stage, which, as has been seen, ex- 
