126 EVENINGS AT THE MICROSCOPE. 



them at their will. But each lancet has a singular pro- 

 jection from its back, which appears to act in some way 

 as a guide to its motion, probably preventing it from 

 slipping aside when darted forth, for the bulbous part of 

 the sheath, in which these projections work, seems formed 

 expressly to receive them. 



Thus we see an apparatus beautifully contrived to 

 enter the flesh of an enemy : the two lancets finely 

 pointed, sharp-edged, and saw-toothed, adapted for 

 piercing, cutting, and tearing ; the reversed direction 

 of the teeth gives the weapon a hold in the flesh, and 

 prevents it from being readily drawn out. Here is an 

 elaborate store of power for darting them forth, in the 

 numerous muscle-bands ; here is a provision made for the 

 precision of the aim ; and, finally, here is a polished sheath 

 for the reception of the weapons and their preservation 

 when not in actual use. All this is perfect; but something 

 still was wanting to render the weapons effective, and 

 that something your experience has proved to be supplied. 



The mere insertion of these points, incomparably finer 

 and sharper than the finest needle that was ever polished 

 in a Sheffield workshop, would produce no sensible result 

 on our feelings ; and most surely would not be followed 

 by the distressing agony attendant on the sting of a bee. 

 We must look for something more than we have seen. 



We need not be long in finding it. For here, at the 

 base of the sheath, into which it enters by a narrow neck, 

 lies a transparent pear-shaped bag, its surface covered all 

 over, but especially towards the neck, with small glands 

 set transversely. It is rounded behind, where it is entered 

 by a very long and slender membranous tube, which, 

 after many turns and windings, gradually thickening 

 and becoming more evidently glandular, terminates in 

 a blind end. 



This is the apparatus for preparing and ejecting a 

 powerful poison. The glandular end of the slender tube 



