VOL. IV.] Recent Literature. 107 



the spore, but that of these three usually but one persists, the 

 first two formed being disorganized soon after they are cut oflF, so 

 that in the ripe spore but one of these is to be readily seen. This 

 small cell he considers homologous with the antheridium of the 

 heterosporus Pteridophytes. This antheridial cell often divides 

 into two, a small stalk-cell, and a larger one which represents 

 the real generative part. He found that wherever this anther- 

 idial body was pluricellular, that it was always formed before the 

 dehiscence of the sporangium. 



As the pollen-tube grows, the generative cell of the anther- 

 idium becomes detached and passes down the pollen-tube, where 

 it divides into two cells which must be regarded as homologous 

 with the sperm-cells of the lower archegoniates. In the Cupres- 

 sineae both cells are functional, and thus two archegonia may be 

 fertilized by a single pollen-tube; in the Abietineae, however, 

 only one of the two sperm-cells appears to be functional. In the 

 meantime the nucleus of the pollen-tube has also divided, but 

 these nuclei take no apparent part in the process of fertilization, 

 contrary to the earlier views of Strasburger and others. Fertili- 

 zation is effected by the discharge of the contents of the genera- 

 tive cell through the end of the pollen-tube into the archegonium. 



From a study of the three genera of the Gnetaceae — Guetnm, 

 Ephedra, and Welzvitschia, our author concludes that the}^ repre- 

 sent the end members of three separate lines of development 

 within the Gnetaceae, which together with the other Gymnos- 

 perms have had a common origin lower down in the system. 



After a careful study of the alleged differences in the male and 

 female nuclei with reference to different stains, he comes to the 

 conclusion that this difference depends entirely upon the amount 

 of cytoplasm taken up by the nucleus for its nourishment. In 

 all cases he claims that the nuclein itself is " kyanophil" — that 

 is, has a special avidity for blue stains, when compared with the 

 cytoplasm; in all cases during nuclear-division the nuclear-seg- 

 ments are distinctly kyanophil. He therefore concludes that 

 when the female nucleus is erythrophil it is due to the presence 

 in it of unassimilated cytoplasm. 



• The second part of the work deals with the formation and 

 structure of zoospores and spermatozoids, and the process of fertil- 



