186 
SUMMARY OF CURRENT RESEARCHES RELATING TO 
rliizoids, the cell-wall of Chara does not exhibit the reactions of 
cellulose. 
Protoplasmic Currents in the Characese.* — Herr G. Hormann has 
investigated the effect of various external irritants on the circulation 
of the protoplasm in Chara and Nitella. Mechanical irritation produces 
no effect. Changes of temperature and changes in the concentration of 
the medium cause a temporary arrest of the motion. A weak electrical 
current suspends the circulation in the entire cell. In Nitella the 
author believes he lias established the existence of a power of active 
motion of the chlorophyll-grains independently of the protoplasm. 
Algse. 
Hew Genera of Plankton- Algae.f — Herr E. Lemmermann gives the 
distinctive characters of a number of plankton-Algae, all provided with 
long bristles. They include species — some of them new — of the genera 
Golenlcinia, Bichteriella , Phythelios , and Lagerheimia, of which fresh 
diagnoses are given, also the following new genera: — 
Franceia g. n. Cellulae singulae v. in coloniis consociatae, libere 
natantes, tegumentis hyalinis mucosis circumvelatae, setis longis basi 
non incrassatis instructae ; chlorophorae 2-3, parietales ; nucleus amyla- 
ceus, singulus, saepe desens ; contentus cellularum vacuola singula 
donatus ; propagatio divisione cellularum in unam longitudinalem direc- 
tionem. Separated from Golenlcinia and Phythelios. 
Chodatella g. n. Cellulae libere natantes, solitariae v. 2-3 in tegu- 
mento cellulari communi dispositaB, ovales v. ellipsoideae, in utroque fine 
setis 2-pluribus longis non in tuberculis sedentibus, basi evidenter 
incrassatis, instructae ; chlorophora singula, parietalis ; nucleus amylaccus, 
singulus ; propagatio sporis v. autosporis (2-8) ; setae autosporarum post 
ruptionem cellulae maternae evolutae. Separated from Golenlcinia , Lager- 
heimia, and Oocystis. 
Schroederia g. n. Cellulae singulae, libere natantes, fusiformes, rectae 
v. arcuatae v. spiraliter contortae, utroque polo spina instructae ; chloro- 
phora singula, parietalis, granulo amylaceo centrali praedita ; propagatio 
bipartitione cellularum. Separated from Beinschiella. 
Nucleole and Karyokinesis in Spirogyra.J — The following are the 
more important points established by Herr C. van Wisselingh. 
The nucleole has a distinct membrane. The most important portion 
of the contents consists of one or two beautifully coiled nucleolar threads 
or tubes ( Schlauchen ) ; if there is only one nucleole in the nucleus, it 
contains two ; if there are two, each nucleole contains one such tube. 
In S. crassa there are two forms of karyokinesis, with and without 
formation of segments. 
In the former case, the larger portion of the framework of the nucleus 
forms ten necklace-like nuclear threads, which, by contraction, produce 
ten nuclear segments. The threads become shorter and thicker, and 
assume the form of tubes with a thick wall. The contents pierce both this 
* Studien iib. d. Protoplasmastromung b. d. Cliaraceen, Jena, 1898, 79 pp., 12 figs. 
See Bot. Ztg., lvi. (1898) 2 ta Abth., p. 342. 
f Hedwigia, xxxvii. (1898) pp. 303-12 (1 pi., 4 figs.). 
X Bot. Ztg., lvi. (1898) pp. 195-226 (1 pi ). 
