ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 263 



abundant protoplasm, swell out on the shaded side of this portion and 

 grow into a lobe, one cell of which developes into an archegonium. 

 The ultimate position of the archegonium is between two lobes which 

 inclose it like a funnel and serve to hold the moisture which is essential 

 to its impregnation. From experiments made by the author, it would 

 appear that an abundant supply of nutriment is favourable to the forma- 

 tion of female, a scanty supply to the formation of male prothallia. 



In the mode of formation of the spermatozoids the author's conclusions 

 differ somewhat from those of previous observers. He states that in 

 none of the higher cryptogams does a disappearance of the nucleus of 

 the mother-cell take place ; the nucleus, on the contrary, developes 

 directly into the spermatozoid, the cilia being formed from the cell-pro- 

 toplasm. The bladder which is so frequently attached to the posterior 

 part of the spermatozoid, he regards as the remains of the mother-cell. 



The structure of the pro thallium appears to the author to indicate 

 that the Equisetaceae are more nearly allied to the Lycopodiaceae than 

 to the Filices. 



Leaves of Sigillaria and Lepidodendron.* — M. B. Renault states 

 a number of well-preserved leaves of Sigillaria have been met with in 

 a railway cutting near Dracy-Saint-Loup. They are long and rigid, and 

 in transverse sections are subtriangular. In the centre of the section is 

 a single vascular bundle. The outermost layer consists of an epidermis 

 composed of thickened rectangular cells. 



The transverse section of the leaves of Lepidodendron selaginoides is 

 rhomboidal in shape, the greater diameter being horizontal. In the 

 centre of the section is a single vascular bundle ; between the bundles 

 and the edges of the leaf are two round cavities. Occasionally these 

 cavities, which are only to be found at the base of the leaf, are filled by 

 a group of large cells. The author suggests that the destruction of these 

 cells may have formed a secretory canal. 



Muscinese. 



Absorption of Water and its Eelation to the Constitution of the 

 Cell-wall in Mosses.j — Mr. J. E. Vaizey chose Polytrichum commune 

 for his observations on the absorption of water in mosses. He obtained 

 stems of this species some 15-20 cm. in length, and placed them with 

 their cut ends in water, about half an inch being below the surface. 

 Placed in a cool room with a dry atmosphere, in less than half an hour 

 all the leaves except the last half-dozen nearest the water were withered. 

 The author then treated sections from various parts of the plant with 

 different reagents. From the reactions obtained it is obvious that the 

 epidermis of the seta, apophysis, and sporangium is strongly cuticularized, 

 and that there is on the outside of the epidermis a distinct cuticle. 



The hypodermal sterome appears from the reaction to contain both 

 lignin and cutin, and consequently must be regarded as suberized. 

 From the condition of the cell-walls, the leaves are the chief organ for 

 absorbing water, as well as for carrying on assimilation in the oophyte. 



Peristome of Mosses.* — M. Philibert states that great differences 

 exist in the structure of the external peristome in mosses. In a small 

 number of families (i. e. Neniatodontere) it is composed of filaments 



* Comptes Eendus, cv. (1887) pp. 1087-9. t Ann. of Bot., i. (18S7) pp. 147-52. 

 X Rev. Bryol., xiv. (1887) pp. 81-90. Of. thi^s Journal, 1887 p. 275. 



