K.—BOTANY 189 
PLATE I—REFERENCES. 
‘Fics. 1-8. Utricularia cornuta. Side and front view of the trap. ‘The 
broken lines indicate the set and relaxed conditions. 
Fic. 2. Front view of the entrance. 
Fic. 3. Sagittal section of the entrance showing the relations of door and 
threshold. d,, door in the set position ; d,, door in the open position ; 
d,, door in the normally relaxed position; d,, door when fully 
relaxed ; d.h., door hinge ; d.t., downward thrust of the lateral hinge ; 
o.t., direction of thrust of the door exerted by the overhang ; and the 
resultant thrust (c) when the trap is set. On the right the lure gland. 
Fic. 4. View of the door as from beneath. m.p., middle piece; /.A., 
lateral hinge ; w.h., upper hinge. Cells in lighter outline are those of 
the inner course. m.r.d.e., middle reach of the door edge ; J.r., lateral 
reaches. 
Fic. 5. Threshold. 7.z., inner zone ; m.z., middle zone ; 0.2. (v.), outer 
zone which bears the velum ; d.h., door hinge ; g., gland which may 
act as a lure. 
Fic. 6. Transverse section of door and adjacent structures: (1) in 
the set position; (2) relaxed after actuation. This section is 
approximately one through arrow e, Fig. 3. 
Fic. 7. Transverse section (arrow d, Fig. 3) of the door through the 
upper region of the middle piece. The broken lines indicate position 
taken when the door is opening. 
Fic. 8. Transverse section of the door near the free edge (arrow c, 
Fig. 3). ¢., the heavy line indicates the inner edge of the threshold ; 
d., dotted line indicates the lower surface of the door edge. The two 
oblique arrows indicate the direction of thrust of the lateral hinges on 
the middle piece (m.p.). When the door is opened the middle piece 
bends along the sagittal line. 
