tort] CURRENT LITERATURE 167 
Development of banana pollen.—An extensive investigation of three 
races of the edible banana (Musa sapientum) has shown that they can be 
f 
be designated as vars. univalens, bivalens, and trivalens. The volume of the 
nuclei, but not their surfaces, is in the ratio 1:2:3. With the increase in the 
number of chromosomes came disturbances in the development of pollen, 
some of the chromosomes not passing to the poles, but remaining behind and 
forming extra nuclei. The size of the tetrad varies in a given anther, although 
the number of chromosomes in the entire tetrad is constant. Sometimes as 
many as eight pollen grains are formed from a single mother cell. 
Prochromosomes are easily distinguished in the pollen mother cell, and 
in Musa Dole TiscHLER was able to show that the number of prochromosomes 
was equal to the diploid number of chromosomes. Probably there is a fusion 
of prochromosomes at synapsis. The splitting of chromosomes at the strep- 
sonema stage TISCHLER regards as genuine and not merely apparent.—CHARLES 
CHAMBERLAIN 
arthenogenesis in Taraxacum.—Parthenogenesis in Taraxacum has 
been investigated again, this time by ScHKORBATOW” who writes in Russian, 
but adds a summary in German, from which the following points are taken: 
The removal of anthers does not in any way affect the germination of seeds. 
Various colors of seeds, like clear green and dark brown, may become fixed 
and hereditary. At metaphase of the first division in the embryo sac, the 
chromosomes show various and characteristic forms, but the chromosomes 
seldom take the arrangement belonging to the heterotypic mitosis, and when 
they do, the author regards the phenomena as atavistic. itotic divisions 
occur in the embryo sac, in the endosperm, and in early stages of the embryo, 
in the last case all the nuclei but one becoming resorbed, so that the cells are 
left uninucleate—CuHartEs J. CHAMBERLAIN. 
The origin of the vacuole.—Probably most botanists believe that the 
large vacuoles of plants arise by the coalescence of numerous smaller ones. 
A paper by BEnstry, dealing with the canalicular apparatus of animals, 
gives also a description of root tips and the tapetum of anthers. The fixing 
agent used was: neutral formalin (freshly distilled), 10 cc.; water, 90 cc.; 
potassium bichromate, 2.5 g.; mercuric chloride, 5.0 g. With this fixing 
** TISCHLER, G., Untersuchungen iiber die Entwickelung des Bananen-Pollens. 
I. Archiv. fiir Zellforschung 5:622-670. pls. 30, 31. 1910. 
* SCHKORBATOW, L., Parthenogenetische und apogame Entwickelung bei den 
Bliithenpflanzen. Entwickelungsgeschichtliche ciao an Taraxacum officinale 
Wigg. Bot. Institut Charkow. pp. 43. pl. 1. figs. 4. 19 
*3 BENSLEY, R. R., On the nature of the canalicular ears of animal cells. 
Biol. Bull. 19:174-194. figs. I-3. 1910. 
