ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 611 



mediately above the Pseudomonites bed, which is now generally accepted 

 as an equivalent of the Noric stage of the Alpine Keuper. 



X-Generation and 2X-Generation.* — J. P. Lotsy discusses the rela- 

 tion between the two generations, sporophyte and gametophyte, from the 

 point of view of the number of chromosomes in the nucleus. The 

 nuclei of the latter contain only half the number of chromosomes found 

 in the nuclei of the former. Which generation should be called the 

 ^-generation ? If the sporophyte, then the gametophyte becomes the 

 ^-generation ; if the gametophyte, then the sporophyte is the 2z-gener- 

 ation. The author points out that the ^-generation is the primitive 

 generation, and that the 2»-generation is later, its double number of 

 chromosomes being due to fertilisation, and cannot exist indefinitely, 

 sooner or later forming reproductive cells in which the primitive number 

 of chromosomes is restored by separation of the paternal and maternal 

 chromosomes. Numerical reduction of the chromosomes is the expression 

 of the pairing of the kinds. In animals the body represents the 2x~ 

 generation, and the sexual cells are the ^-generation. 



Arbee, E. A. N. — On some New Species of Lagenostoma, a type of Pteridospermous 

 Seed from the Coal Measures. 



[Describes two new species which show a close general agreement to the 

 three species of the genus known previously. In one species, L. Kidatoni, 

 the seeds are naked, in the other, L. Sinclairi, they were enclosed in a 

 cupule recalling that of L. Lomaxi. In both cases the seeds were on the 

 ends of the finer branches of a compound frond with reduced lamina, 

 probably of the Sphenopteris type. 



Proc. Boy. Soc, Series B. lxxvi. (1905) pp. 245-59 (2 pis.). 



Correnb, C. — Gregor Mendel's Briefe an Carl Nageli 1866-1873. (G. Mendel's 

 letters to C. Nageli.) [Forming a supplement to Mendel's published work on 

 hybridisation.] Abhandl. Math. Phys. El. K. Sachs. Ges. Wiss., 



xxix. (1905) pp. 189-265. 



Henry, A. — Forests, Wild and Cultivated. (Lecture given before the Royal Dublin 

 Society.) Econom. Proc. B. Dublin Soc, i. (1904) pp. 231-47, pis. ix.-xx. 



CRYPTOGAMS. 



Pteridophyta. 

 (By A. Gepp, M.A., F.L.S.) 



Chinese Ferns.| — H. Christ has examined the collections of Chinese 

 ferns preserved in the Paris Museum, and gives a list of 254 species, 39 

 of which are described as new, as also are some score of varieties. He 

 has studied the distribution of the species, the mingling of the Malayan 

 and northern elements, the local peculiarities, the affinities of the species, 

 and so forth. Several changes of nomenclature are made. Neocheirop- 

 teris replaces the generic name Cheiropteris, which is employed for an 



* Biol. Centralbl. xxv. (1905), pp. 97-117. 



t Bull. Soo. Bot. Franoe, lii. (1905) pp. 1-69 ; Hedwigia, lxiii. (1905) BeibL 

 pp. 152-3. 



