ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 191 



there is a disk- or crescent-shaped mass — the pole-plate. Beyond each 

 pole-plate there is a granular aggregation of archoplasm, from which 

 towards the close of the karyokinetic process there extend radiations 

 into the surrounding cytoplasm. In the late stages the daughter-nuclei 

 move further and further apart as the fibres disappear. 



Aleurone Grains of Grasses.* — A. Guilliermond contributes some 

 remarks upon the aleurone grains of grasses. The grain is a spherical 

 spongy mass, one of the interstices of which contains a very large 

 globoid. During the earlier hours of germination, the proteid is 

 partially dissolved, and the aleurone grain is transformed into a little 

 vacuole occupied by one or two large granules which represent the 

 insoluble part of the proteid, while near or upon the edge of this vacuole 

 are numerous globoids. Subsequently the proteid entirely dissolves and 

 nothing remains but the globoids, which also dissolve by the tenth day. 

 The aleurone grains of grasses are analogous to those of the lupin, but 

 have less proteid, which is nothing but a thin layer around the globoids, 

 while the globoids themselves are of smaller size, also the proteid is in- 

 soluble in potash after fixation in alcohol. This type of aleurone grain 

 is found in wheat, rye, oats, and barley ; maize is similar, but the 

 globoids are larger and there is rarely more than one in each grain. 



Structure and Development. 

 Reproductive. 



Fertilization in Cypripedium.t — L. Pace has investigated the 

 phenomenon of fertilization in Cypripedium spectabile and parviflorum. 

 and less fully in pubescens and candidum. It appears that two cells are 

 formed by the mother-cell, but no wall is formed in the second 

 division, even when the nuclei of both " daughter-cells " divide, as may 

 rarely occur. Two megaspore nuclei are used in the formation of the 

 embryo-sac, and may be related to double fertilization. The completed 

 embryo-sac has only four nuclei. Double fertilization is probably 

 constant, and the primary endosperm nucleus results from the fusion of 

 the polar nucleus, one synergid and one male nucleus. 



Endosperm of four nuclei has been found. The presynaptic nucleus 

 gives evidence of the pairing of threads, probably of paternal and 

 maternal origin. The gametophyte has 11 chromosomes, the sporo- 

 phyte has 22, while the" endosperm probably has 33. An interesting 

 comparison is made of the successive stages of development of the 

 animal egg and of the eggs of Lilium and Cypripedium respectively. 

 These two genera show only one more division from the mother-cell to 

 the egg than in the maturation of the animal egg, and thus have the 

 fewest divisions reported in the angiosperms. 



Development of Saxifraga granulata.^ — H. 0. Juel has investigated 

 the development of Saxifraga granulate, with the following results. The 

 nucleus of the embryo-sac-mother-cell contains a single homogeneous 

 chromatin -thread during the synapsis and spireme stages, in the next 



* Comptes Rendus, cxlv. (1907) pp. 768-770. 



t Bot/Gazette, xliv. (1907) pp. 353-74 (4 pis., 1 fig.). 



I Nov. Act. Reg. Soc. Sci. Upsala, i. (1907) pp. 1-39 (4 pis.). 



