6 Mr. J. Miers on the Menispermacese. 



ovule is now partly free from the placentiferous angle of the 

 cell, but most generally it becomes at length adherent to it 

 after the excentric growth and apparent duplicature of the ovary. 

 It is incorrect to say, regarding this development, that the two 

 halves of this curvature are brought together till they unite in 

 order to form the incomplete dissepiment in the manner above 

 described. The circumstance which St. Hilaire mentions as the 

 cause of the metamorphosis appears to me, on the contrary, the 

 result of an agency which he has entirely overlooked, and to this 

 source only the apparent duplicature can be referred. My ob- 

 servations tend to the conclusion that it originates in a peculiar 

 expansion and induration of the placenta within the cavity of 

 the cell, to which cause alone is to be attributed this excentric 

 growth of the ovary ; for, in those cases where the placenta does 

 not become expanded, no such duplicature occurs. In the in- 

 stance of Cissampelos, cited by St. Hilaire, it may be seen that 

 the linear placenta first protrudes and extends itself at right 

 angles with the side of the ovary, in the direction of the centre 

 of the cell, and that the growth of the pistil on that side is at the 

 same time arrested, in consequence of which the style and the 

 base of the ovary preserve nearly their original distance, while 

 the growing force is all expended on the opposite or dorsal side, 

 thus producing the hippocrepical appearance described. By 

 observing a section of a half-matured seed of Cissampelos, the 

 development of the pseudo-dissepiment may be seen distinctly, 

 when the nourishing vessels belonging to the placenta can be 

 traced in the centre of this line of extension, reaching to its ex- 

 tremity, like an imbedded umbilical cord, which is found in the 

 same position after the whole has become ossified. There is no 

 appearance of any duplicature of the pericarpial covering of the 

 ovary, and its subsequent agglutination, as described by the 

 eminent botanist referred to : it will be foimd to exist only in 

 the endocarpial portion. The development, as I have explained 

 it, is even more evidently demonstrated in the seed-vessels of 

 Ileocarpus and Stephania, where the hippocrepical cell is formed 

 round a flat, solid, orbicular disk, in the substance of which the 

 nourishing vessels can be traced, as in the pseudo-dissepiment 

 of Cissampelos. 



In a group which I have called Heterocliniea, the growth is 

 somewhat varied : there, in the early stage, the ovule is attached 

 as described in Cissampelos ^ but the placenta, from which it is 

 suspended, is like a broad oval disk upon the inner face of the 

 cell j and while the ovary continues to increase equally in all 

 directions, the increment about the placentary space is somewhat 

 less : this face of the cell thus gradually assumes a convex shape 

 inside, and the placenta swells into a globular figure, forming 



