270 THE MICROSCOPICAL NEWS. 
the lower part of the body. As soon as it begins to be formed 
there is an increase of the coloured bodies at the corres- 
ponding point in the endoderm, and can be seen by the naked 
eye. The ovum in its first formation consists of ectoderm cells, 
with a very large number of the smaller forms. In a few hours 
there may be seen embedded among these cells (one which 
has become larger and clearer than the rest, and possesses a dis- 
tinct spot in the centre, which, when fully developed, forms the 
c=) 
Fig, 63. Fig.62. Fig. 64. 
ripe ovum. The ovum then consists of a clear transparent mass 
of protoplasm (zv7/e//us) in which is also a clear space (the germinal 
vesicle) containing another body (the germinal spot). I have had 
several eggs from HZ. vulgaris and i. viridis, but they differ in 
various respects. That of 4. vulgaris is larger and rougher on its 
outer surface (fig. 63), and is covered with short spines. On the 
outer envelope dark triangular shaped spots can be seen. ‘The 
ovum of & viridis is covered with an irregular network. The 
outer envelope is not transparent, and it disappears before hatch- 
