i84 



The ripe eggs are transparent objects, perfectly spherical, and 

 float h-eely in the water. If left undisturbed they slowly rise 

 to the surface and remain there. Any slight movement of the 

 water, however, causes them to move away from the surface. 

 It is possible that the spawn described by Mr. Trouwbridge in 

 his evidence before the Commission of 1898 may have been 

 some such floating eggs. 



The majority of the eggs (Plate I, ligs 1-7) do not vary 

 much in diameter. Out of 50, of a number taken from a 

 female 34 inches in length, 17 were "89 millimetres in diameter 

 (the maximum), one was -85 (the minimum), the average 

 being '88. 



The surface of the eggs when examined with a high power 

 of the microscope shows usually a series of short cross 

 striations. The yolk itself is clear, and a layer of protoplasm 

 may usually be seen at its periphery (fig. i) ; this may become 

 heaped up in the form of a typical germinal disc, though no 

 fertilization has taken place, as shown in fig. 2. If not fertilized 

 by the spermatozoa from the male, howevei, the yolk in a few 

 hours begins to disintegrate, and the whole egg slowly sinks to 

 the bottom. 



The yolk contains one oil globule which presents great 

 uniformity in size, being '17 millim. in diameter. This oil 

 globule moves about freely in the yolk, as can readily be 

 ascertained by rolling the egg along a slide under the 

 microscope. 



Fertilization, which in nature is left more or less to chance, 

 may be readily ensured by procuring the milt from the male 

 and mixing it in the same jar of water with the ova. 

 Ova of 'the White Stiuiipnose treated in this way soon 

 shows a segregation of the protoplasm to one point, and 

 this mass then becomes divided into two. Subsequently 

 each of these segments become divided again into 

 two, and this is repeated till the whole mass is a 

 collection of small divisions. Fig. 3 shows the general 

 aspect of a fertilized egg in which the germinal mass is divided 

 into about 32 parts, and figs. 4 and 5 show a still later 

 stage in which division has proceeded further, and the 

 germinal disc begins to spread out over the yolk. Fig. 4 is a 

 lateral view like fig. 3 ; fig. 5 shows the same egg as it 

 normally comes to rest when left to float freely in the water ; 

 the heavier germinal disc being lowest, and the movable oil 

 globule, of less specific gravity, being uppermost, a ventral 

 view is thus presented of the segmenting mass. This process 

 does not proceed with the same rapidity even among eggs 

 fertilized together. Thus when some of the eggs presented the 



