RmZOCARPE^E 



33 



;se bodies are therefore developed entirely within the microspore, 

 ile the microspores themselves are set free completely from the 

 (range. As in the Salviniaceae, the whole of the contents of the 

 ther-cell is not used up in the formation of the antherozoid ; a por- 

 1 remains behind in the form of a roundish turbid lump consisting of 

 itoplasm and starch-grains, which gradually becomes clearer, and 

 iches itself, in the form of a vesicle, to the antherozoid, which in 

 alaria becomes soon detached, but in Marsilea remains attached to 

 antherozoid during the greater portion of the period of ' swarming.' 

 len the antherozoids are mature the exospore of the microspore 

 ■sts at its apex, and the endospore swells up into a hyaline bladder, 



Fig. i6. — Pilularia globulifera L. Longitudinal 

 section of megaspore. a, coat of spore ; b, c, 

 tf, the threelayers of the epispore. (After Luers- 

 sen, magnified.) 



Fig. 17. — Marsilen. salvatrix. Micro- 

 spore discharging antherozoids. ex^ 

 exospore ; dl, endospore ; zz, anthe- 

 rozoids ;yy, their vesicles with starch* 

 grains. (After Goebei, X350.) 



ch finally bursts to allow of the escape of the antherozoids with their 

 icles. In Pilularia the antherozoid consists of only four or five coils 

 ■X a few vibratile cilia ; in Marsilea it is of considerable length, the 

 pe of a corkscrew, and consists of twelve or thirteen coils, the vibra- 

 cilia being also of great length. The antherozoids collect, in large 

 nbers, in the funnel-shaped depression of the epispore of the mega- 

 re above the prothalHum (see fig. 15), and force themselves, through 

 neck' of the archegone, to its central cell. 



In its early stages the development of the oosperm or impregnated 

 phere corresponds to that of Salviniaceae. After becoming invested 

 1 a.. cell-wall of cellulose, the first segmentations give- ri^e to, .the 



