EARLY STAGES OF DEVELOPMENT OF THE BABBIT. 119 



aud drawn in aqueous humour. The result of measurement 

 was — 



Larger segment .... '099 mm. x '068 mm. 

 Smaller segment .... -090 „ x '060 „ 



No. 3 was also in two segraeutSj aud was examined, measured, 

 aud drawn in aqueous humour. Result of measurement : 



Larger segment .... -100 mm. x -079 mm. 

 Smaller segment .... '096 „ x "071 „ 



No. 4>, the nearest specimen to the uterus, was as yet unseg- 

 mented, possibly an immature or unfertilised one, as the ovum 

 completely filled the space within the zona pellucida. I could 

 not find auy trace of polar bodies. 



All three specimens from this rabbit, which were in two seg- 

 ments, I examined most carefully, to find, if possible, evideuce 

 of the marked difference in appearance described by van 

 Beneden. I treated all with 2 per cent, osmic acid and used 

 weak staining solutions of picro-carmine and aniline blue- 

 black, of picro-carmine, of Beale's carmine and aniline 

 blue-black respectively, but to no purpose. They were then 

 mounted in glycerine jelly, and now, after the lapse of 

 a year, I still fail to find any difference between the two 

 segments. 



From another rabbit I obtained two specimens in the two- 

 segment stage, but was unfortunately only able to make a very 

 cursory examination. One of these I thought I distinguished 

 as having a larger darker segment and a smaller clearer one, 

 but I could only examine it while lying on the folds of the 

 Fallopian tube, the unevenness of which might easily have 

 caused one segment to appear darker. So 1 cannot advance 

 even this instance in support of there being a marked difference 

 in appearance between the two segments. 



Another rabbit, with ova aged 25 1 hours, gave me four, of 

 which two were in the two-segment stage, and two showed four 

 segments. Here again there was no perceptible difference. I 

 did not measure these while fresh. One I have since measured. 



