AZOLLA AND SALVINIA. 



529 



urements in the mature organ. All the protuberances un- 

 dergo the same changes, those next the base of the nucleus, 

 (or those first developed, or the uppermost,) being the most 

 precocious. A nearly mature capsule will present a complete 

 series of the developments. 



First they appear as small sessile protuberances with slight 

 indications of cellularity and a central cavity (PI. CXXVII. 

 Fig. I., 1.) In the second stage one or two cells will be found 

 to have been developed under the original protuberance, 

 which is now therefore more or less pedicellate. The cellu- 

 larity of the head or terminal part is more evident, it is evi- 

 dently hollow, and the cavity contains grumous matter (PI. 

 CXXVII. Fig. I., 2.) As it goes on enlarging the head as- 

 sumes a spherical form, the pedicel becomes more developed, 

 the grumous mass larger (PI. CXX. Fig. IV. 1, 2, 3.) 



Then in the cells of the heads, which are the young secon- 

 dary capsules, amylaceous granules (for they are violetted by 

 indigo) appear. And at this period, if the grumous mass be 

 closely examined, very minute cells will be seen in it, each 

 cell containing 3 or 4 nuclei, PI. CXXVII. Fig. I., 4, 4a, 4b. 

 (or perhaps three or four cells, each containing a nucleus) 

 convex exteriorly, trifacial interiorly.* 



The enlargement continuing, the next stage presents the 

 formerly grumous mass as cellular, the membrane of the 

 cells [the parent cells) not well developed, with grume along 

 their contiguous faces. (PI. CXX. Fig. Ill, 1 T V, PL 

 CXXVII. Fig. I.,9a.) In each of these cells are 3 or 4 yel- 

 low nuclei presenting more or less of their original connection, 

 or quite distinct. Examined separately each of these pre- 

 sents a convex surface and a trifacial one, the last being the 

 surface of their former contiguity. The parent cells soon 

 cease to be evident, and then the cavity of the s. capsule ap- 

 pears filled more or less with trifacial yellow cells. PI. 

 CXXVII. Fig. I., 6. 



* Trifacial if three are developed as is most usual, quadrifacial, if four. 



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