ZOOLOGY AND BOTANY, MICKOSUOPY, ETC. 605 



large size, and possesses cilia attached to a blepharoplast which forms a 

 spiral of five turns. By the absorption of the intervening tissue of the 

 nucellus, a free passage is formed between the pollen-chamber and the 

 prothallus. The embryos, which are formed singly at the lower ends 

 of the archegones, as in Cycas, possess long suspensors, and come to 

 occupy a common cavity formed by the absorption of the tissue of the 

 prothallus. 



The author corrects his previous close comparison between the micro- 

 sporange of Stangeria and the sporauge of Angiopteris. He is now 

 rather disposed to compare the ovule of Cycads to a sorus consisting 

 of a single sporange, which dcvelopes on the whole in a manner similar 

 to a microsporange. 



Division of the Megaspore in Erythronium.* — Mr. J. H. Schaffner 

 finds that, in Erythronium albidum and americanum, the megaspore arises 

 from the archesporial cell directly, by differentiation and not by divi- 

 sion. The cell in which the reduction takes place has a period of 

 development extending over six months. While the nucleus is expanding 

 in the autumn, the chromatin network begins to thicken until a con- 

 tinuous band is formed. In the spring the band twists itself up into 

 twelve loops, which break apart and form twelve very large coiled chro- 

 mosomes. The chromatin granules never appear very distinct, and they 

 do not begin to divide until the chromatin band begins to form the loops. 

 After the pseudo-reduction, the chromosomes are arranged on the spindle- 

 threads with their closed ends turned outwards, and are then gradually 

 untwisted and pulled apart at the middle. This results in the transverse 

 division of each chromosome, one transverse half going to each daughter- 

 nucleus. The division of the megaspore of Erythronium is, therefore, 

 essentially the same as in Lilium philadelphicum. The writer regards a 

 transverse qualitative division as the only possible interpretation. 



Vermiform Sexual Nuclei in Caltha.f— Miss Ethel N. Thomas finds, 

 in the embryo-sac of Caltha palustris, a much-coiled vermiform male 

 nucleus wrapped round the polar nucleus. There is every reason to 

 believe that a fertilisation of the polar nuclei by a vermiform nucleus 

 actually takes place in Caltha palustris as in Lilium Martagon. 



Germinal Vesicles of the Abietineae.f — Herr W. Arnoldi has in- 

 vestigated the nature of the structures called by Hofmeister " germinal 

 vesicles " (Keimblaschen) in the Abietineae, and has determined that they 

 are not " proteid-vacuoles " (Eiweissoacuolen), but are the nuclei which 

 have passed out from the cells of the "covering-layer" (DecJcschicht). 

 There are not, in the archegones of the Abietineae, any simple or com- 

 pound proteid-vacuoles ; the nuclei of the covering cells pass from them 

 into the ovum-cell (oosphere) itself. They then lose their nuclei and 

 become the " germinal vesicles " of Hofmeister, " Hofmeister's cor- 

 puscles " of Goroschankin. The Abietineae do not stand alone among 

 the Coniferae in possessing these bodies ; they appear to be wanting 

 only in the Cupressineae and the Taxodineae. 



* Proc. Anier. Ass. Adv. Sci., xlviii. (1899) pp. 299-300. 



+ Ann. of Bot., xiv. (1900) pp. 318-9. 



% Flora, Ixxxvii. (1900) pp. 194-204 (1 pi.). 



