achromatic parts of the mitotic figure. Spirogyra subeqgua and S. jugalis 
were the principal forms studied. The sequence in .S. subegua is as follows: 
The resting nucleus has a large nucleolus surrounded by a very evident 
nucleolar membrane and the threads of the nuclear network are very faint. 
As division begins the nucleus elongates, the nucleolus loses its membrane 
and puts out processes which extend to the periphery of the nucleus. At 
this stage striations are distinctly visible in the plasma heaps at the poles of 
the nucleus. The nucleolar processes are now withdrawn and the nucleolus 
shows a differentiation into intensely Staining granules and a less deeply = 
Staining ground substance. Achromatic threads now appear inside the nucleus 
and represent a continuation of the achromatic threads outside. The granules 
continue to stain more deeply and the nuclear membrane disappears, begin- a 
ning at the poles of the nucleus. The granules, or chromosomes, become oF | 
arranged in a single layer_in the nuclear plate, while the less deeply staining 
substance takes the form of bows with sides resting on the chromosomes and 
the apices, to which the achromatic threads are attached, turned toward the 
poles. The chromosomes split and as the halves of the nuclear plate separate, 
granular threads connect them for a time. 
After the formation of a new nuclear membrane the material of the nuclear 
plate still shows the intensely staining chromosomes imbedded in a less 
deeply staining mass from which processes reach to the nuclear membrane. 
The processes are gradually withdrawn, the chromosomes gradually become 
indistinguishable from the rest of the mass, the nucleolar membrane appears 
and the nucleolus assumes the ordinary aspect of the resting condition. 
The other species studied differed only in unessential details.—Cnas. J. 
CHAMBERLAIN. 
370 BOTANICAL GAZETTE [NOVEMBER | 
A MONOGRAPH of the Caul p *has recently app d from the Annales 
of the Botanical Garden of Buitenzorg. Madame Weber-Van Bosse presents 
a complete taxonomic account of these interesting plants, based upon a per — 
sonal and very extensive examination of the various scattered herbaria. 
There is perhaps no group of alge more difficult to handle than the cauler- 
pas, and the skill with which the author has reduced the immense number = c 
described forms and varieties to sixty-four species is admirable. The specific 
descriptions seem excellent and fifteen fine lithographic plates greatly at 
the reader. One must regret, however, the absence of an index to Pe 
and synomyms, for an index, although a clerical detail, is indispensable to es 
the complete usefulness of such a work, oe 
It is exceedingly interesting that this genus Caulerpa, immense 1? = 
number and diversity of its varieties, and cosmopolitan in its dite oe 
through the warmer waters of the globe, should apparently reproduce Ae : 
*5 WEBER-VAN Bosse: Monographie der Caulerpes. Ann. d. Jar. Bot. d. B ; 
20T§ 15 > 243-401. 1808. 2 
