440 OBSERVATIONS ON THE STRUCTURE 



reality agrees with its ordinary structure in Phaenogamous 

 plants. 



I shall endeavour to establish these two points ; namely, 

 the agreement of this description with the usual structure 

 of the Ovulum, and its essential difference from the ac- 

 counts of other observers, as briefly as possible at present ; 

 intending hereafter to treat the subject at greater length, 

 and also with other views. 



I have formerly more than once^ adverted to the struc- 

 ture of the Ovulum, chiefly as to the indications it affords, 

 even before fecundation, of the place and direction of the 

 future Embryo. These remarks, however, which were 

 certainly very brief, seem entirely to have escaped the 

 notice of those authors who have since written on the 

 same subject. 



In the Botanical Appendix to the Account of Captain 

 Plinders' Voyage, published in 1814, the following de- 

 cription of the Ovulum of Cephalotus foUicularis is given 

 " Ovulum erectum, intra testam membranaceam continens 

 sacculum pendulum, magnitudine cavitatis testae," and in 

 reference to this description, I have in the same place 

 remarked that, from "the structure of the Ovulum, even 

 in the unimpregnated state, I entertain no doubt that the 

 radicle of the Embryo points to the umbilicus."^ 



My attention had been first directed to this subject in 

 1 809, in consequence of the opinion I had then formed 

 640] of the function of the Chalaza in seeds -^ and some 

 time before the publication of the observation now quoted, 

 I had ascertained that in Phaenogamous plants the un- 

 impregnated Ovulum very generally consisted of two 

 concentric membranes or coats, enclosing a Nucleus of 

 a pulpy cellular texture. I had observed also that the 

 inner coat had no connection either with the outer or 

 with the nucleus, except at its origin ; and that with 

 relation to the outer coat it was generally inverted, while 

 it always agreed in direction with the nucleus. And, 



1 Flinders' Voy. ii, p. 601 (_Ante, p. 77), and Linn. Soc. Tramac. xii. p. 136. 



^ Flinders' Voy. loc. cit. 



^ Linn. Soc. Tratisac. x, p. 35. 



