480 SUMMARY OF CUREENT RESEARCHES RELATING TO 



cutting off three peripheral segments and originating the primary axial 

 cell within, which on division gives rise to the cover cell and the central 

 cell. 5. The central cell on division forms the primary neck canal cell 

 and the ventral cell. 6. The cover cell is active for a time, cutting off 

 peripheral segments for the outer cells of the neck and basal initials for 

 the canal row. 7. The number of basal initials varies, but is at least 

 three in G. undulata. 8. The cells of the canal row and the peripheral 

 cells of the neck grow by intercalary divisions, and in any order. 9. 

 The major growth of the archegonium is intercalary. 10. The cells of 

 the neck canal row have a double origin. The lower are formed by the 

 intercalary divisions of the primary neck canal cell ; the upper through 

 the intercalary divisions of the three or more initials cut from the base 

 of the cover cell. 11. The ventral cell divides relatively early into 

 ventral canal cell and egg. 12. The ventral canal cell is variable in size. 

 13. The mature archegonium has usually more than fifty neck canal 

 cells, and may contain as many as eighty-six. 14. The canal row is 

 generally multiple in its upper part, and occasionally throughout. 15. 

 The disintegration of the canal row is acropetal, but does not involve 

 the ventral canal cell. 16. If the number of neck canal cells is an 

 indication of primitiveness, the most advanced group of the mosses 

 (Polytrichacege) has the most primitive archegonium yet described among 

 the Bryophyta. 



Spermatogenesis of Polytrichum juniperinum.* — C. E. Allen, 

 having previously described the "Cell-structure, Growth, and Division in 

 the Antheridia of Polytrichum juniperinum "f as far as the formation of 

 the androcyte mother-cells, now treats of the metamorphosis of the 

 androcytes into antherozoids. 1. Each newly formed androcyte contains 

 a small rounded blepharoplast which behaves like a centrosome in the 

 division of the androcyte mother-cell, and is situated where recently was 

 a spindle pole. 2. This blepharoplast elongates, places itself in contact 

 with the plasma membrane, and ultimately forms a long, peripherally 

 placed, curved cord-; and two long ciha grow out from it, being attached 

 to it a little behind its anterior end. 3. The nucleus moves into contact 

 with the blepharoplast and stretches out alongside it. The blepharoplast 

 ultimately becomes indistinguishable from the nucleus, save at its pro- 

 jecting anterior end. The nucleus becomes a long, slender, coiled, finally 

 homogeneous body, of about one and a half turns ; and with the 

 blepharoplast it seems to constitute the whole antherozoid. 4. When 

 the blepharoplast begins to elongate, a large spherical body, the limo- 

 sphere, appears, variously situated in the cytoplasm ; and soon it 

 approaches the anterior end of the blepharoplast. It then divides un- 

 equally, the smaller portion becoming the apical body, and the larger 

 remaining unchanged and retaining the name of the limosphere. 5. The 

 apical body long remains in evidence, but does not appear to form part 

 of the antherozoid. 6. The limosphere becomes placed in contact with 

 the posterior portion of the nucleus, and persists in the cytoplasm until 



* Ann. Bot., xxxi. (1917) pp. 269-91 (2 pig,)- 

 t Arch. f. Zellforsch., viii. (1912) p. 121. 



