60 Mr. Griffith on the Ovulum of Santalum album. 



Voyage, in the Appendix to vol. ii. p. 569, that the ovula are attached to the 

 apex of a central receptacle, must therefore be received with slight limi- 

 tation. 



The ovula in this genus have, I believe, in general a marked correspondence 

 in number with the stigmata, the number of both being most commonly three. 

 In the very young buds, as, for instance, those of a line in length, the future 

 ovula are indicated by papilliform bodies of a homogeneous pulpy structure. 

 They are, as it were, appressed to the surface of the placenta ; they soon, how- 

 ever, become elongated, and appear truncate at the apex, which is minutely 

 papillose. The next change takes place apparently with great rapidity, and 

 consists in the protrusion of a tubular membrane from the centre of the apex 

 of the ovulum, in which no opening could be detected previously. This tubu- 

 lar membrane passes down at first in the direction of the axis of the ovulum, 

 but becomes immediately recurved, and passes up on one side of the ovulum, 

 and in close apposition to the placenta. 



I have not hitherto seen this membrane in the earlier stages of its formation. 

 At the period to which I have alluded above, the tube may be traced to the 

 point of attachment of, or base of the ovulum, where it ends, or rather begins, 

 in a cul de sac. Immediately at its exit it is somewhat enlarged, but the 

 diameter soon narrows, and continues so until it dilates again at the apex, 

 which frequently shows a tendency to division. Throughout the ascending 

 part of its course it is in close apposition with the placenta. Generally each 

 tube reaches to the apex of this body ; and at this point, and occasionally 

 throughout other portions, mutual and tolerably firm adhesion takes place. 

 Each tube is a simple, membranous, closed sac, containing a great number of 

 molecules, which are exceedingly active, especially about the time of expan- 

 sion of the flower. These molecules vary much in size, the variety depending 

 apparently upon degrees of combination, the very small ones being alone 

 simple. The motion consists of a rapid oscillation, and is frequently accom- 

 panied with considerable change of place ; the molecules frequently approach- 

 ing each other and then receding, the line or course which they describe 

 being very irregular. The motion is much more vivid in those parts of 

 the tubes in which the least aggregation of the molecules has taken place. 

 These always appear to be least abundant in that part of the tube contained 



