AZOLLA AND SALVINIA. 



531 



sules) developed. This also occurs at a very early period, 

 when the two subsequently difform organs are recognisable, 

 the one by the smallness and great number of the papillae, 

 the other by their larger size and smaller number. 



The second discrepancy arises from the greater develop- 

 ment of a particular cell in the secondary capsules resulting 

 from the development of the papillae. Otherwise, at least up 

 to the period of the enclosure of the trifacial cells (or spores) 

 of the smaller sphaerical secondary capsules, the developments 

 are so much the same that they may be advantageously con- 

 sidered together. 



In both, the first steps consist in the development of the 

 cells of the superficies of the secondary capsules. (PI. CXXV 

 Fig. III. ,2.6, c, d, e.). Shortly after, a cavity begins to appear 

 in the secondary capsule, and this cavity then becomes filled 

 with the usual formative grumous matter. (PI. CXXV. Fig. 

 I., a, b., PI. CXXVI. Fig. II., 5.). It is in this grume that ail 

 the subsequent changes of importance take place. 



The first of these exhibits a variable number of irregular 

 granular nuclei (or coagula or condensations) in the grume, 

 w T hichsame coagula soon exhibit (except in cases of abortion) 

 traces of being surrounded by a membrane. PI. CXXVI. Fig. 

 III., 2a, 2b, 3, 3a. etc. 



A little later each secondary capsule will be found to pre- 

 sent a central mass of grume apparently connected with the 

 inner surface of the secondary capsule by radiating grumous 

 lines (PI. CXXVI. Fig. II., 2b.) the intertices of which are 

 very generally occupied at least partly by distinct cellular bo- 

 dies with one surface trifacial. On slightly pressing the se- 

 condary capsules the grume escapes, and then presents, if at- 

 tentively examined, a few nuclei or coagula as before said, and 

 a considerable number of faintly defined cells, in most of 

 which traces are to be seen of ternary or quaternary division, 

 and as many nuclei ; also a few small trifacial cells, as above- 

 mentioned. 



The grumous mass of the secondary capsules resulting 



