406 DEVELOPMENT OF OVULE. [BOOK i. 



nised, intended as the basis of the nucleus, which does not 

 afterwards increase in thickness. Above this line the apex 

 forms itself into the nucleus, and below it the substance of 

 the axis expands and forms a protuberance, which extending 

 itself as a kind of membranous fold gradually covers in the 

 nucleus (Integumentum primum aut internum, mihi ; Secundine, 

 Mirb. ; Membrana internet, Auct.) Sometimes soon after, 

 and indeed almost contemporaneously with this, sometimes 

 later, sometimes immediately below the first protuberance, 

 at other times at some distance from it, as, for instance, in 

 many Buckwheats (Polygonacese) and Rockroses (Cistacese), 

 we may next observe a second protuberance, which, as the 

 second integument, covers in the first (Integumentum secundum 

 sive externum, mihi; Primine, Mirb.; Testa, Auct.). The 

 first-formed integument certainly does frequently consist only 

 of a fold of the epidermis of the nucleus ; nevertheless, we 

 find a tolerably thick parenchyma taking part in its formation 

 in almost all those families which form no second integument, 

 and also in some which possess both coverings, as, for instance, 

 in Spurgeworts (Euphorbiacese), Rockroses and Daphnads 

 (Thymelacese)." 



END OF VOL. I. 



LONDON : 

 BRADBURY ANT) EVANS, PRINTKRS, WHITEFRIARS. 



