418 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
iiucleus and ovum-nucleus is completed at tlie base of the ovum-cell. 
After impregnation the ovum-nuclens travels to the germinal spot. 
In the Characeae nuclear division takes place karvokinetically in all 
meristematic cells, directly only in the cells of the mature enveloping 
tubes and internodes. Centrosomes were nowhere seen. 
As to the systematic position of the Characete, Goetz adopts Cohn’s 
view, separating them from the Algae, and constituting them into a 
distinct class which he calls Phycobrya, having its nearest affinity with 
Mosses. 
Algae. 
Regeneration in Algse.* * * § — Herr E.deWildeman describes the mode 
of regeneration of dead growing points by the proliferation of adjoining 
cells through the dead terminal cell, in Cephaleuros and Trentepohlia , 
•comparing it with the so-called false branching of the Schizophyceae ; 
also the renewal of the thallus of Phycopeltis from the marginal cells 
and from the adjoining cells of old portions of the thallus. He con- 
cludes that all the cells of filiform algae are capable, after injury or 
death of adjoining cells, of producing new cells by division, to regene- 
rate the destroyed portions of the thallus. 
Pyrenoids.f — Investigations by Prof. Chmjelewsky on the cultiva- 
tion of Hyalotheca lead him to the conclusion that, in this case, the 
pyrenoids are not of the nature of a reserve-deposit of proteids, but 
•are independent organs of the cell, the function of which is at present 
unknown. 
Life-History and Cytology of the Fucaceae.J — Continuing their 
examination of various species and genera of Fucaceae, Prof. J. B. 
Farmer and Mr. J. LI. Williams state that, in the development of the 
oogones, the first papilla possesses the same number of chromosomes 
as the rest of the somatic cells ; but that, after the stalk is septated off, 
and during the first division of the nucleus of the oogone itself, the 
number has been reduced by one-half. The nuclear divisions are 
associated with the presence of centrospheres, in which centrosome-like 
structures can sometimes be seen. In the expulsion of the oospheres 
from the oogone a considerable part is played by mucilage. In the 
normal process of impregnation only a single antherozoid enters the 
-oosphere. Groups of antherozoids are attracted to the unfertilised 
oospheres; while, after impregnation has been effected, a definite re- 
pulsion of the antherozoids is seen. When the fertilised oosphere 
undergoes segmentation, the nucleus possesses twice as many chromo- 
somes as there were in the oogonial mitoses, and this double number is 
retained throughout the life of the plant, except in those divisions which 
lead directly to the production of sexual cells. 
Abnormal Conjugation in Spirogyra.§ — Herr Schmula describes 
an abnormal mode of conjugation in Spirogyra nitida, in which one cell 
* Mem courron. Acad. r. de Belgique, lviii. (1899) 19 pp. See Hedwigia, 
xxxviii. (1899) Beibl., p. 85. 
f S.B. Bot. Sect. Naturf.-vers. Kiew, Aug. 28, 1898. See Bot. Centralbl., lxxvii. 
(1899) p. 108. 
t Phil. Trans. R.S., cxc. (1898) pp. 623-45 (6 pis.) Cf. this Journal, 1896, p. 656. 
§ Hedwigia, xxxviii. (1899) Beibl., pp. 1-3 (2 figs.). 
