20 GAEL GOTTFRIED HARTMAN 



The yolk in the eggs of No. 58 is distributed more evenly and 

 in smaller granules than in tubal eggs described above, but the 

 three regions may be made out. These eggs, if freed of albumen 

 and shell, would be almost exact counterparts of the eggs just 

 entering the Fallopian tube (Nos. 56 and 76). In the prepara- 

 tions the shrunken shells measure 0.25 x 0.22 mm. in diameter; 

 the ovum proper, however, measures 0.125x0.092 mm.; about 

 the same as the eggs of Nos. 56 and 76. 



The polar body and egg chromosomes occupy the same rela- 

 tive positions as in the tubal ova. There is normally no 'peri- 

 vitelline' space, as described and figured by Selenka. Some- 

 times, indeed, the zona pellucida cannot be disinguished, the 

 protoplasm of the egg grading off, somewhat abruptly it is true, 

 into the albumen layer, and in these cases no zona can be seen. 

 Among some 230 preparations only rarely do I find any space 

 between the egg and the albumen, hence I believe that the 

 'perivitelline space' of Selenka is an artefact due to shrinkage. 

 In several eggs of batch No. 54 the protoplasm was slightly 

 shrunken away from the zona, not the zona from the albumen. 

 Yolk is eliminated in the 2- and the 4-celled stages, and lies 

 between the blastomeres and the zona. After this the blasto- 

 meres become closely applied to the albumen layer, with the 

 zona pellucida still apparent between the two in some cases. 



When observed in the fresh state in the uterine liquid or in 

 Ringer's solution the young eggs resemble markedly a half- 

 cooked grain of tapioca or sago. The shell and albumen form 

 a hyaline, almost transparent envelope with a white granular, 

 rather opaque central core, which is the egg proper. The shell 

 is turgid and well rounded out. As the fresh egg may measure 

 through the shell 0.4 to 0.5 mm. (e.g., D text fig. 4, page 34) the 

 albumen layer is seen to be much thicker than that of Dasyurus 

 and the study of the small ovum in the center correspondingly 

 more difficult (fig. 4). In the fixing fluid the albumen becomes 

 so opaque that the egg cell can scarcely be seen, especially when 

 the fixing fluid contains no osmic acid to differentiate the egg 

 by the black stain of its yolk. On prolonged immersion of the 

 egg in alcohol, the albumen clears up somewhat, so that the 



