-192 Journal of Applied Microscopy 



interprets — and doubtless correctly — as centrosomes. When spores are about 

 to be formed, a progressive cleavage takes place in the multinucleate protoplasm 

 until the protoplasm becomes divided into very small portions, each containing 

 a single nucleus. The cleavage is independent of nuclear division. The spores 

 have two cilia attached to a basal body just beneath the plasma membrane. It 

 is too early even to suggest whether this body should be homologized with the 

 blepharoplast of higher forms. Two delicate threads connect this body with the 

 nucleus. After the spores comes to rest, the pyrenoid, which diappears at the 

 beginning of segmentation, again becomes visible. There is no organized chro- 

 matophore. c. j. c. 



Juel, H. 0. Zur Entwickelungsgeschichte des Prof. Juel collected this curious para- 



Samens ^oxv Cymmwnum. Beihefte zum g^g ^h^jg travelling in Tunis. The 

 Botanischen Centralblatt, 13: 194-202, 1902. . , . ° 



material is quite refractory. Flem- 



ming's solution was used for fixing, and the material was left in the bath in hard 



paraffin for a week and then would not ribbon, but had to be cut with the knife 



oblique, as when cutting celloidin.* 



The behavior of the megaspore-mother-cell is peculiar. At its first division 



two very unequal cells are formed, the one nearest the micropyle being the 



smaller. The smaller cell divides longitudinally and the larger one transversely, 



thus giving rise to a tetrad of four megaspores, of which only the one nearest 



the chalaza becomes functional. These peculiarities are habitual, haying been 



observed in twenty cases. Fertilization takes place four days after pollination, 



and sixteen days after pollination embryos of various sizes were found. The 



antipodals do not divide, as has been claimed by Pirotto and Longo, but may be 



distinguished as three undivided cells even after the endosperm has become 



abundant. In the ripe seed the embryo is a small, spherical mass of cells with 



no suspensor or differentiation into body regions. c. j. c. 



Johnson, D. S. On the Development of Cer- The species investigated were Piper 



tain Piperaceae. Botanical Gazette, 34 : adunca, P. medium, Heckeria umbellata 



321-340, pis. 9-10, 1902. 



and H. peltata. The embryo-sac devel- 

 ops in the usual way, there being no indication of a sixteen-nucleate sac, as in 

 Peperomia. In both genera there is an extensive formation of endosperm before 

 the first division of the fertilized egg. In Piper the endosperm begins with free 

 nuclear division, the walls appearing later, while in Heckeria walls are formed 

 from the first. In both, the embryo is very small and undifferentiated, except 

 that there is a rudimentary suspensor. The flowers of Piper and Heckeria are 

 more complex than those of Peperomia. 



In germination, the endosperm protrudes from the seed coats and continues 

 to invest the embryo until the cotyledons and root are differentiated, c. j. c. 



* Sometimes material which infiltrates perfectly with two hours immersion in the bath, and 

 ribbons nicely, becomes very hard and refractory after a prolonged immersion. c. j. c. 



