AND THE LOWER ANIMALS. 251 



latter in all stages of development, and, in infinitely 

 greater number, undergoing on the spot, and in the 

 midst of the liquid of the general cavity, those 

 changes which in the aphis take place in the various 

 chambers.* Here, then, we find that constancy of 

 fundamental phenomena on which I dwelt in the 

 earlier pages of this volume. This harmony is of 

 itself alone a proof of the accuracy of the investiga- 

 tions made and the structures figured by the two 

 observers, no matter what be their method of inter- 

 preting them. 



In the viviparous Aphides, Huxley describes and 

 figures a very different series of phenomena. Here 

 the ovarian chamber is filled with a pale homogeneous 

 substance, which encloses a dozen cells with opaque 

 nuclei. Portions of this material are separated from 

 the rest by a constriction of the walls of the chamber, 

 which becomes more and more decided. It is from it 

 that the new being will be entirely developed. In the 

 midst of this little mass there may indeed be seen a 

 small transparent sphere, which sometimes presents 

 within it a nucleus like those of the preceding cells, 

 but of which occasionally there is no trace, and which 

 under other circumstances is replaced by a little mass 

 of rounded corpuscles. To experienced eyes there is 

 nothing here to recall either the true germinal vesicle 

 or the germinal spot, the fundamental elements of ova 

 properly so called. 



I unhesitatingly express the same opinion, in regard 

 to the small transparent sphere, which Lubbock found 



* Viewing the subject from this aspect, it is interesting to com- 

 pare the figures in my memoir with fig. 2, plate 40, of Huxley's 



essay. 



