ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 287 



The microspores of the first group have three separable mem- 

 branes, of which the two outer ones are coloured brown, the inner- 

 most blue by zinc chlor-iodide. The granular spiny epispore has 

 three fissures uniting at the apex, through which project ridges of 

 the clear homogeneous exospore. The exospore is again the first- 

 formed of the three. The spore contains oil-granules and a nucleus. 

 After the separation of the lenticular prothallium-cell, the anthe- 

 ridium-cell divides first of all into two, and each of these two again 

 into four cells by three oblique walls ; these walls again do not show 

 cellulose reaction ; each of the cells contains a nucleus. By further 

 division the antheridium consists of four inner cells entirely sur- 

 rounded by eight outer cells. Each of the four inner cells then 

 divides into a number, the mother-cells of the antherozoids, which 

 float in a granular mucilaginous mass resulting from the deliques- 

 cence of the walls of the outer cells. 



In the second group of Selaginella the microspores have only two 

 separable membranes, the inner one of which only gives cellulose 

 reaction ; but the outer one is divided into two layers, the outermost 

 of which is spiny. The processes of internal division are in the main 

 the same as in the first group, but there are only two inner primary, 

 surrounded by eight outer cells ; from the two inner ones are developed 

 the mother-cells of the antherozoids. The antherozoids, on escaping, 

 are still enveloped in a small globular membrane ; they have only 

 two cilia. 



These observations bring the mode of formation of the antheridium 

 in the Selaginellaceae much more into harmony with that in the other 

 Archegoniatse than appeared from the descriptions of Millardet and 

 Pfeflfer. In all cases the primordial cells of the antheridium arise 

 from a single cell by successive divisions ; some of these primordial 

 cells break up, by a wall parallel to the outer surface, into the inner 

 mother-cells of the antherozoids and the outer enveloping cells. 



The author considers the establishment of a special class, the 

 Ligulatfe, for the heterosporous Lycopodiacese as very unsatisfactory, 

 there being no sufficiently good general characters for it. Nor does 

 he consider the differentiation of microspores and macrospores as a 

 good basis for classification. 



Influence of the Direction of the Light on the Division of the 

 Spores of Equisetum.* — According to Prof. E. Stahl, the direction 

 in which the division of the nucleus takes place in the spores of 

 Equisetum is dependent on the direction of the rays of light, the two 

 daughter-nuclei lying in that direction. The nucleus at the greater 

 distance from the source of light is that of the root-cell, the one 

 nearer to the source of light that of the prothallium-cell. The former 

 is therefore on the side of the spore which is turned away from the light. 



Calamites of the Coal-measures.t — Herr C. E. Weiss enters at 

 great length, and in great detail, into the structure and systematic 



* Ber. Deutsch. Bot. Gesell., iii. (1885) pp. 334-40. 



t Abhandl. Geol. Spezialkarte v. Preussen, v. (1884), 8 figs, and an atlas of 

 28 pis. See Bot, Centralbl., xxiii, (1885) p. 310. 



