1847.] Linnean Society. 325 



linia. The poUinia are erect, have no diaphanous margin, and de- 

 hisce along that margin which is internal with regard to the cell of 

 the anther, and which presents no appreciable difference of structure, 

 but corresponds with the margin of dehiscence of the pendulous pol- 

 linia first noticed by Mr. Brown. The base of the stigma is slightly- 

 papillose in D. Rafflesiana, and more evidently so in the other spe- 

 cies ; and the fissures of communication are open in the former, but 

 closely approximated in the latter. In neither has Mr. Griffith seen 

 the poUinia engaged in these fissures, but they are either caught 

 by the processes of the corona or fa^ to the fundus of the corolla ; 

 and in whatever situation they emit their boyaux, the cord formed 

 by the aggregation of the latter always engages itself in the 

 nearest fissure where it becomes more opake and grumous. The 

 cord then passes upwards to the base of the stigma, along which it 

 is reflected until it reaches the union of the stigma with the styles, at 

 which place it dips into one of them, or rarely both, and proceeds 

 downwards to the placenta, causing a slight discoloration of the ad- 

 joining tissue. The boyaux then separate and proceed in every di- 

 rection among the ovula, to which they become firmly attached. 

 They contain much granular matter Avhich has a strong tendency to 

 accumulate towards their termination. Mr. Griffith states that he 

 has observed an oscillatory motion, but no motion of ascent or de- 

 scent, of the contained granules. The tubes are simple and one ap- 

 pears to be allotted to each ovulum, to which it remains appHed for 

 some time, invariably passing in at the centre of the fissure and ad- 

 hering so firmly that they break across rather than separate. Mr. 

 Griffith was unable to demonstrate their termination internally by 

 actual dissection, but in one instance he observed the boyau to ter- 

 minate about the fundus of the fissure in a cul-de-sac, which was 

 crowded with granules. Whatever the function of these granules may 

 be, similar bodies exist in the cellular tissue of the ovula both before 

 and after the application of the tubes, and the majority certainly dis- 

 appear before the tubes reach the ovula. 



No immediate change appears to be produced in the ovula by the 

 application of the tubes ; but some time afterwards the excavation 

 appears to enlarge and extend towards the point of insertion of the 

 tube ; and this action is continued until the whole of the granular 

 mass disappears and the chief part of the ovulum is occupied by the 

 now empty excavation. No further appreciable change, except in 

 size, takes place for some time, and the rudiments of the coma are 

 even visible before any part of the embryo appears to be formed. 



