ZOOLOGY AND BOTANY, MICROSCOPY, ETC. 
651 
Division of the Nucleus in the Asci of Peziza.* * * § — Herr S. Gjurasin 
finds, in the formation of the ascospores of Peziza vesiculosa , a mode of 
indirect division of the nucleus differing somewhat from that in the 
Exoasceae, the only group of fungi in which karyokinesis has at present 
been definitely detected. The method of staining employed was that of 
Flemming and Herrmann. The chief point in which the process differs 
from that in Endomyces is that the nucleole remains in existence until 
the division of the nucleus is complete. There is also less divergence 
of the elements of the spindle from one another, and the chromatic 
elements are less strongly differentiated. 
Wall of Vacuoles. t — By the use of a 1 p. m. solution of coffein, 
which causes slow contraction of the membrane, Dr. T. Bokorny has 
obtained further evidence of the invariable presence of a membrane or 
tonoplast surrounding the vacuoles in living cells. It is a portion of 
the protoplasmic contents of the cell, and is comparable in its properties 
to the parietal utricle. The best objects for observations are epidermal 
cells of the petals of Primula sinensis, Cyclamen europseum, and Tulipa, 
especially the red cells. 
( 2 ) Other Cell-contents (including- Secretions}. 
Distribution of Mannite and Dulcite.J — According to Herr A. N. 
Monteverde, the presence of these substances is especially characteristic 
of the order Scrophulariaceae. Of 797 species belonging to 109 genera 
of this order, mannite was found in 272 species and 36 genera, dulcite 
in 26 species and 4 genera. They never occur together in the same 
species, and only in two instances in the same genus. Mannite was 
also found in a few Orobanchaceas, in Jasminiese, and in two species of 
Umbelli ferae ; dulcite in several Celastraceae. In RMnanthus, Euphrasia, 
and Melampyrum they are distinctly plastic substances, resulting from 
the transformation of sugar. 
Distribution of Calcium oxalate. — Prof. J. Borodin § distinguishes 
between two modes of deposition of calcium oxalate, differentiated and 
diffused ; the former where it takes place in special cells, the latter 
where it is distributed in all the cells of a tissue. In leaves diffused 
calcium oxalate occurs especially in the epiderm ; when present in the 
mesophyll, it is usually confined to palisade-parenchyme. It may occur 
in the form of separate crystals, clusters, or sphaGritic structures. Out 
of 913 (Russian) species of Angiosperms examined, 318 contained dif- 
ferentiated, and 40 diffused calcium oxalate, while in 548 this salt was 
entirely wanting in the leaves. The greater number in which the dif- 
fused form was present belonged to the Gamopetalse. 
Prof. R. Chodat and M. G. Hochrentiner |] record the occurrence of 
crystals of calcium oxalate in cells of the stem of Comesperma scandens, 
the internal coating of which is completely cutinized. 
* Ber. Deutsch. Bot. Gesell., xi. (1893) pp. 113-7 (1 pi.). 
f Biol. Centralbl., xiii. (1893) pp. 271-5. 
X ‘ Ueb. d. Yerbreitung d. Mannits u. Dulcits,’ 37 pp. See Bot. Centralbl., 1893, 
Beih., p. 199. 
§ Arb. St. Petersb. Naturf. Gesell., 1892, 56 pp. and 1 pi. See Bot. Centralbl., 
liv. (1893) p. 210. 
|| Arch. Sci. Phys. et Nat., xxviii. (1892) pp. 495-6. 
