W. HOFMEISTER ON THE DEVELOPMENT OF ZOSTEBA. 261 



Fig. 33-35. Embryos of Z. marina. Fig. 33, side view of a young embryo 

 fig. 34, front view of one somewhat older ; fig. 35, seen obliquely 

 from behind. Magn. 40 cliam. 



Fig. 36. Longitudinal section of a half-developed embryo. Magn. 30 diam. 



Fig. 37. Longitudinal section of an almost ripe embryo. Magn. 30 diam. 



Fig. 38. Ripe embryo, in front, back and lateral views. Magn. 4 diam. 



Fig. 39. Longitudinal section of the bud of an almost ripe embryo. Magn. 60 

 diam. 



Fig. 39 b. The end of the stem of the same. Magn. 300 diam. 



Fig. 40. Longitudinal section of the terminal bud of a sterile plant of Z. marina. 



Fig. 41-46. Ruppia rostellata. 



Fig. 41 . Longitudinal section of a young ovary. Magn. 40 diam. 



Fig. 41 b. The ovule of the same. Magn. 200 diam. 



Fig. 42. Longitudinal section of an ovule ready for fertilization. Magn. 60 diam. 



Fig. 42 b. Embryo-sac of the same. Magn. 300 diam. 



Fig. 43. Longitudinal section of an ovule immediately after impregnation. 

 Magn. 40 diam. 



Fig. 43 b. Endostome, papilla of the nucleus and micropyle-end of the embryo- 

 sac of the same. Magn. 300 diam. 



Fig. 44. Longitudinal section of an ovary, some eight days after fertilization. 

 Magn. 30 diam. 



Fig. 44 b. The rudimentary embryo of the same. Magn. 200 diam. 



Fig. 45. Longitudinal section of a farther developed ovary. Magn. 30 times. 



Fig. 45 b. The embryo from it. Magn. 200 diam. 



Fig. 46. Longitudinal section of an almost ripe embryo. Magn. 40 diam. 



[A. H.] 



