>' 



II has been staled, that ilioto is no distinct cuiiclc to l>c found in this pan of (he Stanhopca ; 

 thai is to say, there is no membrane, composed of empty cell*, which can bo discovered cither by 

 tearing it off, or by n vertical .section : such indeed is a general fuel in petals and pctaloid parts. It 

 is probable that in these organs its place is supplied by » great thickening and developemcnt of thai 

 external homogeneous membrane, first noticed by M. Adolplie llrongnlart, afterwards found by 

 Professor Henslow. and subsequently described by myself and oilier*. That it exists in a state of 

 great toughness, in very delicate flowers, has lately been shewn by me in Hydrohonia Meleagris, and 

 in this Stanhopca it is also present, although I did not succeed in detaching it. In general it 

 adheres so firmly to the cells it lies upon, that it merely adds to their thickness, as is shown n( A, B, 

 and C. and cannot be distinguished. But it also rises above the surface in the form of hairs, and 

 then the cell itself has no adhesion to it, but appears in the form of a lax, shrivelled, internal 

 membraneous sac. as at B 2, and elsewhere in that figure; the cell however, if filled with fluid, 

 extends so as to fill the whole cavity of the hair, as at C 3. In this latter case the membrane 

 adapts itself to the surface of the cells, and may bo distinctly seen at their angles. 



Possibly the hairs of plants are generally formed in this way; namely, of homogeneous cuticular 

 membrane, covering cells free at the sides, and only adhering to the parenchyma at I ho base. I am 

 led to Ibis supposition from cornering tlio hair* of Stanliopea. Tradescantla. Campanula lropuneulus. 

 Polystncliya luteola, and others of like nature, all of which are evidently formed upon the same 

 plan, and in which it is probable that the phenomena of circulation may be observed. In these hairs 

 there i, always a nucleus (B 3). in the inside of a sac or cell, which latter distends when wet. and 

 contracts afterwards, or after death, then leaving a considerable space between its sides and those 

 of the hair (B 1). It is in this space, which, when the hair U full of life, is extremely small, that 

 the motion of the fluids take* place, as is manifest in Tradeseanlia and Campanula Hapunculus. 

 I have not. indeed, succeeded in seeing any circulation in the hairs of Stanhopca ; but when they 

 nre killed by iodine the inner sae contracts and becomes more distinct, and then appear on the 

 outside of the sac, especially between its end and the point of the hair, evident traces of a 

 reticulation, which may be supposed to be a plexus of capillar)- laticifcrous vessels, whose contents 

 nre coagulated by the action of iodine. 



Fig. D. represents a portion of the mesochilium. with the horns and part of the epiebilium cut 

 off; this figure is given for the purpose of shewing the foramen that exists between the bases of the 

 two horns, and the nature of which is at present unknown. 



