686 CONSERVATIVE ORGANS. [LECT. XI. 



towards the midrib which unites the lobes. To the 

 naked eye, these spines appear like simple Tmstles ; 

 but when they are examined under the microscope, 

 each spine is found to consist of two distinct parts ; 

 the one (fig. 6. a.), a small cellular papilla; and the 

 other (&.), which is supported on its apex, a firm 

 tapering pointed body, resembling a small, in- 

 verted bodkin. 



This appendage is endowed with so much ir- 

 ritability, that as soon as a fly or other insect 

 alights upon the upper disk of either of the lobes, 

 so as to touch any of the spines, the lobes, if the 

 plant be in a healthy condition., immediately 

 close upon it; and the spines either empale the 

 little animal, or the teeth on the edges of the 

 lobes, crossing one another, prevent its escape, 

 and detain it until it dies. 



The anatomical examination of these lobes does 

 not elucidate the phenomenon connected with 

 their functions. They resemble a leaf in their 

 cellular and vascular structure: the vessels being 

 given off from the midrib in arching fascicles, 

 which anastomose, towards the outer margin of 

 each lobe. The epidermis is glandular, and is 

 probably the seat of the irritability of the ap- 

 pendage; but, I have not had an opportunity of 

 examining it with sufficient care, to enable me to 

 determine in what particulars it differs from that 

 of the leaf. 



