390 Mr. Griffith on Dischidia Rafflesiana. 



of the pitcher and both surfaces of the leaves they are g-reenish, from a deposit 

 of minute green corpuscles (Tab. XVII. figs. 4 & 6). The space between the 

 Stoma and the inner margin of the innermost circle is invariably uncoloured ; 

 any imperfection, when it does exist, is confined to the Stoma, the surround- 

 ing circular tissue being in such instances perfect. The fact Of the existence 

 of Stomata in the inside of these Ascidia, where there can be but a compara- 

 tively small ingress of light and air, is curious enough, particularly when 

 coupled with the deep coloration of the tissue on which they are developed ; , 

 and one is naturally led to ask. Can they have the same functions with those - 

 of ordinary foliaceous structure ? May not the functions of those in which 

 the Stoma is opake be glandular ? 



November 7, 1834. 



EXPLANATION OF TAB. XVII. 



Fig. 1. A portion of the stem of Dischidia Rafflesiana, Wall., bearing a pair of leaves and a 



pitcher ; the latter longitudinally divided : — of the natural size. 

 Fig. 2. A pair of young pitchers ; one well-developed, the other partly abortive. 

 Fig. 3. Stoma, from the upper surface of the leaf, which corresponds to the inner surface of 



the pitcher. 

 Fig. 4. The same, with the bourrelet removed. 

 Fig. 5. Abortive stoma from the surface of the leaf corresponding to the outside of the 



pitcher. 

 Fig. 6. The same, with the bourrelet removed. 



All the figures of the Stomata are viewed as transparent objects, and with triplets of 



J^ and ^j of an inch focus. 



