LECT. XI.] CAULINAR AND FOLIAR APPENDAGES. 687 



Mr. Ellis, who first described this curious 

 appendage*, imagined that the glands were the ir- 

 ritable parts; and that, as soon as an insect 

 touched any of these, the motion of the lobes was 

 produced. Every other succeeding writer has 

 stated, generally, that it is merely necessary to 

 touch the upper surface of the lobes to excite their 

 action. From a variety of experiments, however, 

 I am convinced that no motion is produced until 

 one or other of the spines be touched; and, from 

 the manner in which these are affixed to the pa- 

 pillae, and the connexion of the latter with the 

 cuticle of the lobes, I am induced to suppose, that 

 the touching the spines communicates a thrill or 

 tremor to every part of the surface on which they 

 are situated, which excites into action the irri- 

 tability on which their motion depends. It may 

 be stated as an objection to this opinion, that it is 

 altogether hypothetical ; but no hint that can 

 tend to explain so interesting a phenomenon 

 should be withheld. 



As the intention of this appendage is evidently 



* " The Dionoea was first brought to this country, in the 

 " summer of 1768, by Mr. Young, gardener to the Queen; 

 " and Mr. Ellis described it, and had a drawing and a plate 

 " engraved from a plant which flowered in his chambers in the 

 " following August. It was from this plate and his characters of 

 " the plant, that Linnaeus's description was drawn up for his 

 " Mantissa. '* Vide Smith's Selection of the Correspondence of 

 Linn&us, vol. i. p. 235, and vol. ii. p. 72. 



