HISTOLOGY OF PITCHER PLANTS. 163 



Kow all this is so circumstantial that it is difficult to suppose 

 that the author could have been in error. Yet, I think, that in 

 wliat he says about the structure of the hood, we have a clae as to 

 Avhat it is which he lias seen, and which, misinterpreting, he has 

 described as canals. 



He states that the hoods are formed of elongated cells, between 

 wliich canals run, having communication with another canal running 

 along the edge of the lip ; that these canals contain protoplasm, the 

 column of which can be sometimes seen broken at intervals. In 

 Fig. 13 a group of these cells are shown, having been first bleached 

 and any cell contents that might have been present removed, and 

 the preparation afterwards stained. 



It will be observed that the cells of the lip are elongated, as 

 described, and that they are greatly thickened, of which fact no 

 mention is made ; that in the secondary or thickening deposit a 

 number of simple pits are present, extending to and sometimes 

 appearing to pierce the primary cell-wall, which, being more highly 

 refractive, is easily made out. In Fig. 12 a section of one of these 

 lip-cells is shown in section, exhibiting the same features and also 

 the presence of the greatly developed cuticle which overlays them, 

 but which gradually decreases in thickness, till just before reaching 

 a gland it entirely disappears. So, also, the surface cells, which all 

 have thickened walls, showing simple pits (though not nearly so thick 

 as those forming the lip of the hood), become thin as the glands are 

 approached. 



Now it seems to me that it is either these thickened cell walls or 

 else the primary cell wall which Dr. Tait has described as canals 

 containing protoplasm, the breaks in its column being the simple 

 pits which are always found in such thickened cells, and which, when 

 seen in section, seem to indicate a break in the continuity of the 

 substance. At least this is the only way in which I can account for 

 his being so misled ; but as to the non-existence of the canals I am 

 perfectly satisfied. 



One other point before I conclude. In the mesophyl of Nepen- 

 thes chelsoni there are some curious structures, the interiors of 

 which are lined with a number of very coarse spiral fibres — in one 

 instance I counted as many as seven strands. They cannot be re- 

 garded as true vessels, as they are comparatively short, and their 

 outline very irregular, appearing as though they occupied inter- 

 cellular spaces. Their diameter often varies somewhat abruptly 



