692 General Notes. [ September, 
pectedly, or injuring high-power lenses. The writer by its means 
was enabled to study with great deliberation and certainty, the 
phology and physiology of that great group of jointed animals, 
the insects. 
Equally good results were got by its use in studying the em- 
bryology of the shad, where it revealed to the writer, and for the 
. 
Fic. 2. : ayes 
first time to science, the presence of a so-called polar vesicle in 
the earliest stages of development. é 
In Fig. 2 we have a combination of the familiar animalcule cage -_ 
