Mr. Griffith on the Development of the Ovulum in Avicennia. 7 



Fig. 9. Longitudinal section of an ovulum of this period : the young albuminous mass (the 

 protuberance of fig. 8.) is now seen to be partly exterior to the ovulum. A pollen- 

 tube is still in attachment. The disc represents the rudimentary embryo. 



Fig. 10. Part of the ovulum, the whole of the posterior lateral elongation, now digitate at 

 the end, which is confined in the placenta, and once-branched also within the 

 ovulum, the central or axile prolongation, the now almost entirely exserted albu- 

 men, and the embryo. This figure does not represent a section of the albumi- 

 nous mass, but of the body of the ovulum alone, one side of which was sliced off 

 to expose the albumen. 



Fig. 11. Placenta (entire) of an ovarium some time after fecundation, a. Apex of the pla- 

 centa, b, b. Barren ovula. c. Fecundated ovulum. d. Exserted albuminous mass, 

 showing the furrow or chink ? by which the points of the cotyledons will pass out 

 {A. intermedia). 



Fig. 1 2. Fecundated ovulum ; longitudinal section through the body of the nucleus, but not 

 through the albuminous mass : the tips of the cotyledons reach the furrow or 

 chink. 



Fig. 13. An entire placenta of ^. resinifera at a more advanced period: the letters have the 

 same references ; e. shows the lower edge of the former furrow, now an opening ; 

 d. the large inner Up or edge with irregular margins overlapping the cotyledons. 



Fig. 14. Young seed and embryo about the same period of development : the embryo is 

 removed from the seed, which is viewed obliquely, a. Body of the ovulum or 

 nucleus, b. Fleshy part of the exserted albuminous mass. c. Lower or outer 

 edge of the fissure by which the cotyledons have protruded, d. Inner or upper, 

 now membranous, cellular edge of the same. 



