Chap. XVIII. STEUCTURE OF THE LEAVES. 



447 



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 withjn the bladders of Utricularia. 

 20 



Q-- — - 6 



1 



Fig, 29. 



{Genlisea ornata.) 



Utriculiferous leaf; onlarged about 



three times. 



I Upper part of lamina of leaf, 

 & Utricle or bladder. 

 n Neck of utricle. 

 Orifice. 



a Spirally wound arms, with their 

 ends broken off. 



