May 3, 1912] 
In the subject index no titles are given, but 
references are given to the year and author, 
so that the corresponding title can be easily 
found in the chronological catalogue. 
It is obvious that a scientific bibliography 
like this serves a very useful purpose to the 
student and investigator, especially when it is 
well arranged and possesses a high degree of 
completeness, as is the case here. With 
Sommerville’s book at his command the worker 
in the field of non-Euclidean or n-dimensional 
geometry is unusually well equipped for refer- 
ring quickly to the literature of his subject. 
ArtHuR RanuM 
CORNELL UNIVERSITY 
Report on the Dune-Areas of New Zealand, 
their Geology, Botany and Reclamation. 
By L. Cockayne, Ph.D., F.L.S., Depart- 
-ment of Lands, New Zealand. Printed by 
John Mackay, government printer. 1911. 
Because of extensive dune-areas and the 
impending danger to valuable lands from en- 
croachment, the Dominion government com- 
missioned Dr. Cockayne to conduct a careful 
investigation of the dune conditions in New 
Zealand and to embody certain recommenda- 
tions as to the reclamation of the dune lands 
and the protection of threatened territory in 
a formal report. This report, which is an ex- 
tension of the author’s earlier researches, we 
now have from the government printer. The 
paper is divided into two parts; the first deals 
with the geology and botany of the dune-areas 
and the second with various methods of rec- 
lamation. Jn Part I. the geology of these 
dynamic habitats is very excellently handled 
under such subheads as: The Material of 
Dunes, Dune Building on the Coast, The Ef- 
fect of Solid, Flexible and Inflexible Obstacles, 
and the Effect of Climate, General Topog- 
raphy of the Dune-areas in New Zealand, 
Movements of Dunes and Dune-sand. There 
are more than 300,000 acres of dune lands in 
North and South Islands, where oceur chains 
of sandhills of irregular form, which are gen- 
erally divided in places by basin-like hollows 
of greater or less extent. The wind plays a 
great part in constantly changing the form of 
SCIENCE 
699 
the dunes, the position of the hills, and in 
modifying the slope angles. Hills in all stages 
of growth and decay, and basins in the proc- 
ess of being hollowed out or being filled up ap- 
pear on every side. The wider dune areas 
appear like seas of sand with the ridges as 
more or less stationary billows with their 
scanty vegetation. 
Under “ Botany ” is treated such ecological 
matters as: Climatic Factors, Heat, Light, 
Moisture, Soil, Topography and Biotie Fac- 
tors. The most characteristic plants with 
their growth-forms and adaptations are 
treated in considerable detail. The leading 
dune plants in New Zealand are: Spinifex 
hirsutus _(Graminer); Scirpus frondosus 
(Cyperacee); Huphorbia glauca (Euphor- 
biacee); Carex pumila (Cyperacer); Caly- 
stegia Soldanella (Convolvulacer); and 
Arundo conspicua (Graminex). These plants 
are distinguished as “sand-binders” in dis- 
tinction to the following which are called 
“sand-collectors”: Caprosoma acerosa (Rubi- 
acer); Pimelea arenaria (Thymeleacee) ; 
Cassinia leptophylla, C. fulvida, C. retorta 
(Composite); Festuca littoralis (Graminee) ; 
Calamagrostis Billardieri (Graminex); and 
Scirpus nodosus (Cyperacez). 
The commoner plant associations repre- 
sented are: Sand-Grass Dunes, Pes Capre 
Dunes, Shrub Dunes, Lakes and Swamps, Dry 
Hollows and Stony Plain. The various dune 
species are noted in tabular form with various 
ecological notes. This list includes 147 species 
of which 82 are endemic, 43 Australian and 
15 South American. Fifty-one families and 
104 genera are represented in this number. 
The methods in vogue the world over for 
the artificial fixation of dunes are based upon 
those which nature herself uses and these are 
here enumerated as fifteen “fundamental 
principles” with which plant ecologists are 
more or less familiar. Marram-Grass, Am- 
mophila arenaria, and the Tree-Lupin, Lupinus 
arboreus, are noted as the best of the “sand 
fixers” for the region under consideration. 
The efficiency of these two species is compared 
in considerable detail. Under “Methods of 
Reclamation” the methods of preparing and 
