224 
T. JEFFERY PARKER, 
per cent.), or osmic acid (1 per cent.), and for this purpose the 
specimens were not transferred to alcohol, but to weak glycerine 
(equal parts of glycerine and water), in which they were teased 
out. 
Tor sections showing the cilia of the endoderm, the Hydrcs 
were kept for twenty-four hours in 1 per cent, osmic acid, then 
washed, and preserved in weak glycerine until required for cut- 
ting, The sections were cut by Dr. Pritchard^s very convenient 
freezing microtome, the specimens being placed in gum water 
before freezing. 
