128 



Dorsal sepal about |-inch long, incurved, narrowly con- 

 cave, lanceolate. 



Lateral sepals rather longer than the dorsal, usually 

 slightly divergent, dentate about the middle, beyond which 

 they are narrowly tubular and pointed. Proximal half nar- 

 row and channelled. 



Lateral petals filiform, rather short-er than dorsal sepal. 



Column incurved, almost as long as the dorsal sepal, very 

 widely winged from below the anther. Wings fitted. 



Stigmatic surface circular, just below the anther. 



The winged column forms a vessel shaped somewhat like 

 an ancient Roman lamp, which is capable of being almost 

 completely closed by the labellum. when this is lowered. 



The lahellum is attached to a long semi-circular strap-like 

 claw. It consists of a rather large convex central lobe, about 3 

 lines in diameter, with a beak-like process looking towards the 

 anther, and a shorter curved process looking towards the in- 

 sertion of the lateral sepals. It is not so sensitive as the label- 

 lum in many of the genus pterustyUs, but if a slight pressure 

 be applied to the beak when it is in the raised position this 

 will flatten itself against the claw, and the whole apparatus 

 make a slow and deliberate descent so as to form a lid to the 

 winged column. 



DESCRIPTION OF PLATE XXII. 



A. Pressed specimen from R. C. Gunn's collection of Tasma- 

 nia n orchids (1843). 



B. Shows column (c), labelliim (I), anther fay, pencillato 

 appendage of labellum (apj. All natural size. 



C. Enlargement (x 3) of B. 



