ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 417 



leads to a remarkable complication on p. 316, where the list of 

 luminous fungi strongly reminds one of an algebraic expression re- 

 solved into its factors. On pp. 97-100 BotrycMum Lunaria Sw. is 

 quoted in five several ways. This, however, is a mere incident of the 

 system of giving the authority for the name of every plant mentioned — 

 an excellent practice which we do not remember to have observed before 

 in any botanical text-book. 



Cryptogamia Vascularia. 



AzoUa filiculoides.* — M. Eoze gives details of some observations on 

 Azolla filiculoides Lam. 



Preliminary to the act of fecundation, the antherozoids emitted by 

 the microspores glide under the upper part of the envelope of the mega- 

 sporange ; they then descend the funnel-shaped body which crowns the 

 prothallium, and easily arrive at the archegones. The result of fecunda- 

 tion is the formation of a cellular embryo which rapidly enlarges. 

 The embryo at an early stage presents tha rudiments of the two pri- 

 mordial leaves, and it may be seen to rise to the surface, which it does 

 by the help of a bubble of oxygen which has formed in the upper cavity 

 under the action of solar light. It then emits a lateral root covered 

 with root-hairs which are connected with the two primordial leaves by 

 tracheiform vessels. Prom experiments which the author has made, 

 although the spores may have been submitted to a temperature of 

 — 7° C, they will still retain the power of emitting antherozoids, 

 or producing a prothallium and archegones. The author concludes by 

 calling attention to the curious vital suspension of the embryos of Azolla 

 in their pseudo-cotyledonary period, when the temperature of the water 

 is often about + 5° C. 



Characeae. 



Antherozoids of Characese.j — M. L. Guignard has undertaken a 

 series of observations on the antherozoids of Ghara and Nitella, with 

 a view to discover whether they proceed from the nucleus of the mother- 

 cell in which they are formed, or from the cytoplasm, or from both together. 

 By special methods of fixation, hardening, and staining, the details of 

 which are not given, the author finds that the body of the antherozoid 

 is formed from the nucleus itself. A band of nuclear substance appears 

 on the surface of the nucleus, and grows longer and longer by extending 

 between the two extremities which have first appeared, and becomes 

 twisted spirally as it grows longer. As soon as the outline of the anterior 

 extremity of this filament is discernible, the two cilia may be perceived 

 in the thin layer of hyaline protoplasm which is nearest this extremity. 

 Later on, the cilia, which at first lie up against the filament, become 

 separated therefrom and the protoplasm gradually disappears, being 

 absorbed and used up for the nutrition of the antherozoid, so that only 

 a few granulations are left on the posterior extremity of the filament. 



The latter proceeds altogether from the nucleus of the mother-cell, 

 and moreover gives all the reactions of nuclein ; the vibratile cilia are 

 derived from the cytoplasm, corresponding, in this respect, to the mode 



* Bull. Soc. Bot. France, xxxv. (1888) pp. 427-8. 

 t Comptes Kendus, cviii. (1889) pp. 71-3. 



