Cuar. XIV. ALDROVANDA VESICULOSA. 323 
is slightly concave, and is formed, according to Cohn, 
of three layers of cells. Its upper surface is studded 
with colourless glands like, but more simple than, 
those of Dionza; they are supported on distinct 
footstalks, consisting of two rows of cells. The outer 
Fie. 13. 
(Aldrovanda, vesiculosa.) 
Upper figure, whorl of leaves (from Prof. Cohn), 
Lower figure, leaf pressed flat open and greatly enlarged. 
and broade* portion of the lobe is flat and very 
thin, being formed of only two layers of cells. Its 
upper surface does not bear any glands, but, in their 
place, small quadrifid processes, each consisting of 
four tapering projections, which rise from a common 
