Kerr — Dischidia rajjflesianu and Dischidia nummidaria. ,'30;^ 



the plant tlie materials collected by the ants, while they also confer upon the 

 plant the power of storing up rain-water and substances brougiit down 

 with it. 



Tliere is no analogy for Beccari's tlieory of liereditary gulls. The pitchers 

 have evidently been evolved from flat leaves ; traces of that evolution we see 

 in the ontogeny of the plant, and also in such a form as D. Colli/ris, Wall., 

 whicli has concave leaves with purple under-surface. Pitcliers developed 

 normally on a plant grown iu the Royal Gardens, Kew, thougli no Acari 

 were present.' I have never seen Acari in young pitchers. There is little 

 evidence either for tlie view tliat tlie plant is carnivorous ; dead insects 

 are rarely found in the pitchers ; 1 found none in a large series ; water, 

 in which Delpino says the insects are drowned, is found in only a small 

 percentage of the pitchers ; there are no digestive glands within the 

 pitchers ; and, finally, as Treub and others have pointed out, the roots afford 

 a ready means of escape for any insect which may accidentally enter the 

 pitchers. 



The remaining views give to tlie pitcliers a combination of two or more of 

 the following functions : — 



1. Water reservoirs. 



2. Organs for economizing tlie water-vapour of transpiration. 



3. Receptacles for storing humus, detritus, &e. 



4. Ant-shelters. 



There are several strong objections to the water-reservoir theory, i.e., in 

 the sense that the pitchers either catch rain-water directly or water coursing 

 down the branches of the host tree. In the first place, at least 50 per cent, of 

 the pitchers are incapable of holding water ; if calculated from my figures in 

 the foregoing table, about 6'2 per cent. ; but the direction of the pitchers may 

 be taken as at random and the percentage left at 50, though it must be 

 remembered that a large number of these, owing to their nearly horizontal 

 position, will be able to hold but little water. Water is only found in a few 

 of the pitchers capable of holding it. The pitchers do not naturally occupy a 

 suitable position for catching water, even when pendent ; on the contrary, the 

 close apposition of the mouth to the bark of the supporting branch would seem 

 to indicate an adaptation to avoid the inflow of water. I have before mentioned 

 that many of the pitchers containing water had been accidentally separated 

 from their support, so forming a pocket between it and the pitcher in wliicli 

 water flowing down the branch must of necessity collect, and thence filter 

 into the pitcher. This, however, cannot be considered the normal position of 



' Scott and Sargaut, he. cit. 



3a2 



