DR. W. H. RANSOM ON THE OVUM OE OSSEOTJS EISHES. 
461 
inwards. The breathing-chamber was complete in five minutes, and the funnel of the 
micropyle was effaced in fourteen minutes. During the first shortening of the funnel 
it seemed as if the aperture at its apex also became smaller, but this appearance 
may have been deceptive. This experiment was repeated, the spermatozooids seen 
moving in the apex of the micropyle, and in half a minute a breathing-chamber began 
to form. 
Experiment 6. — I then impregnated similarly five eggs, using no pressure, and 
noted that one egg, which was so placed that the mouth of the micropyle was directed 
towards the stream carrying the spermatozooids, was the first to show indications of being 
impregnated. I saw in this case the spermatozooid enter the mouth of the funnel, but 
could not in this position of the egg trace it any further. This egg showed the breathing- 
chamber 1-^r minute after the testis was applied ; in two minutes more all the eggs 
showed a breathing-chamber, and in every case those eggs which had their micropyles 
directed from the current were the latest to give evidence of being fertilized. 
Experiment 7. — I placed four more eggs in the cage, and applied a fragment of ripe 
testis to the edge of the cover, using no pressure ; one egg was so placed that the mi- 
cropyle could be viewed full face, and the aperture at its apex was brought into focus 
this egg was in the second row, so that the current being diverted by the upper row and 
flowing quickly in consequence of the inclination of this stage, carried the spermatozooids 
wide of it. I watched carefully and painfully Tor seven minutes; no spermatozooid 
approached the micropyle, and no trace of a breathing-chamber appeared. I applied a 
fresh fragment of testis and watched closely for nine minutes longer, still no spermato- 
zooids were seen near the funnel, and no change was seen in the egg, although other 
parts of the egg were in contact with active spermatozooids. I then put another piece 
of testis to the edge of the cover, and turned the cell the other way upwards, so that 
gravity tended to bring the seminal particles back to the egg, which was constantly 
and carefully watched. In two minutes I saw an active spermatozooid enter the apex of 
the funnel and disappear as if inwards : a quarter of a minute more had not elapsed 
before the clear bright circle, which marks the aperture, became indistinct from short- 
ening of the funnel : during the next two minutes I saw three more spermatozooids enter 
the apex, and vanish apparently inwards : ,1-J minute after the appearance of the first 
spermatozooid in the funnel, the yellow droplets became paler: the breathing-chamber was 
complete 3-| minutes later, and the usual vivid contractions of the yelk appeared in 
fifteen minutes. The eggs, two in number, which were in the front row were impreg- 
nated by the first application of the testis. Thus for eighteen minutes, active, moving 
spermatozooids were seen in contact with the yelk-sac, but not in the micropyle, and no 
sign of impregnation appeared ; yet in a quarter of a minute after one was seen to enter, 
the indications of perfected impregnation began and went on in the usual way. The 
fourth egg in this experiment was not impregnated ; it lay in the back row, its micropyle 
closely pressed against one of the eggs in the front row, so that the access of spermato- 
zioods was rendered difficult. These results leave no room to doubt that the function of 
