CHAI-. XVIII. STEUCTUEE OF THE LEAVES. 



447 



....__ yj. 



round the cylinder like a thread round a screw. If the 



cylinder is now removed, we shall have a tube like one 



of the spiral arms. The two projecting edges are not 



actually united, and a needle 



can be pushed in easily be- 



tween them. They are in- 



deed in many places a little 



separated, forming narrow 



entrances into the tube ; 



but this may be the result 



of the drying of the speci- 



mens. The lamina of which 



the tube is formed seems 



to be a lateral prolongation 



of the lip of the orifice ; 



and the spiral line between 



the two projecting edges is 



continuous with the corner 



of the orifice. If a fine 



bristle is pushed down one 



of the arms, it passes into 



the top of the hollow neck. 



Whether the arms are open 



or closed at their extre- 



mities could not be deter- 



mined, as all the specimens 



were broken ; nor does it 



appear that Dr. Warming 



ascertained this point. 



So much for the external 

 structure. Internally the 



lower part of the utricle is covered with spherical 

 papillae, formed of four cells (sometimes eight accord- 

 ing to Dr. Warming), which evidently answer to the 

 quadrifid processes within the bladders of Utricularia. 



Fl - 29 - 



three times. 



I Upper part of lamina of leaf. 

 6 Utricle or bladder. 

 n Neck of utricle. 

 o Orifice. 



a Spirally wound arms, with thcil 

 ends broken off. 



