292 BOTANICAL GAZETTE [ OCTOBER 
attention. During mitosis the structure of the nucleolus is lost, its staining 
power is lessened and it breaks up into.small pieces which show no staining 
capacity. These pieces are taken up by the nuclear thread and are to be 
regarded as condensation bodies of nutritive material. They may form 
plastin for spindles or chromatin for chromosomes. He says that this view 
resembles that of Hertwig, Flemming, and others. If it should be correct, it 
argues against the individuality of chromosomes.— C. J. CHAMBERLAIN. 
N THE WINTER of 1895-6, Bérgesen and Paulsen carried on some impor- 
tant ecological studies in the West Indies. The results of their investiga- 
tions have been published only recently.* The work is divided into two 
main parts: I. The halophytic vegetation, by Bérgesen; II. The forests 
and thickets, by Paulsen. In addition there is an appendix containing a 
statement of the new spermatophytes, and a list of the alge and fungi 
observed. The book is fully illustrated with eleven full-page plates from 
Bérgesen’s photographs, and many text figures. 
The halophytic vegetation is treated of under five heads: 1. The sea 
weeds. Of chief importance are the Halimeda and Caulerpa forms, growing 
‘so densely as to form a solid mass. Some extraordinary Caulerpas are 
‘described, one closely resembling Carex arenaria in its external form. Its 
creeping, sharp-cornered stem sends out assimilation shoots and rootlets. 
2. The vegetation of the sandy beaches. These beaches are composed 
principally of coral fragments, lime, and particles of limy alge. On account 
of the weight of these sand grains no dunes are formed, even by the strongest 
winds. All the plants are protected in various ways against loss of water. 
The blades of grass are rolled up, and on other plants the leaves are bluish- 
gray and often very fleshy. Their elliptical or spatulate forms also give @ 
small proportion of leaf exposure. The runners are above ground, as there 
is no danger of harm by flying sand. The Canavalia has dorsiventral leaves, 
the epidermis is provided with glandular, bristly hairs, some of the cells are 
arranged as stomata but do not function as such, and become crystal bear- 
ing. The Cocoloba has brilliant, upward turned leaves, the upper epidermis 
is strongly cuticularized, without stomata, and is impregnated with tannic 
acid. Many other forms are described, some having water cells, oil glands, 
cells containing calcium oxalate crystals, etc. 
3. The vegetation of the rocky coasts, consisting of characteristic agaves, 
cacti, bromelias, and croton forms. 
4. mangrove vegetation, surrounding and encroaching upon all the 
bays, brackish lakes, and salt ponds, wherever there is found protected water. 
One of the most prominent forms is the Rhizophora, which has two kinds of 
aerial roots. Some spring from the principal stem standing at right angles 
“The vegetation of the Danish West Indies, Copenhagen. 1898. C ae" 
Centralbl. 74 : 143. 1898. 
