61 
ZOOLOGICAL LITLllATURE. 
This paper, though published without the writer^s name, is 
confessedly by the author of the ^ Geographical Distribution of 
Mammals^ (Zool. Record, iii. pp. 3-6), to wliom, of course, the 
theory of Mr. Wallace (founded on a strict extension of the 
principle of Natural Selection, and of which a full abstract is 
given below) is distasteful ; and that theory is met on general 
grounds. 
Natiiusius, W. von. UeberBildung der Schale des Vogeleies. 
Zeitschr. fur die gesammt. Naturwissensch. 1868, pp. 19- 
21 . 
Remarks on the theory and investigations of Drs. Landois 
(Zool. Record, ii. pp. 85, 86) and R. Blasius {op. cit. iv. pp. 
76, 77). 
Ramsay, Edward P. Notes on Birds breeding in the Neigh- 
bourhood of Sydney. Ibis, 1868, pp. 271-280. 
In continuation of the series of articles before noticed (Zool. 
Record, i. p. 65, ii. p. 90, iv. p. 78). The species treated of 
are Monarcha trivh'gatUy Fardalotus pimctatuSy Uirundo frontalis, 
Cisticola ruficepSy and Excalfactoi'ia australis. 
Wallace, A. R. A Theory of Birds^ Nests : showing the Rela- 
tion of certain Sexual Dilferences of colour in Birds to their 
Mode of Nidification. Journ. Travel and Nat. Hist. 1868, 
pp. 73-89. (Translation) Bibl. Univers. Arch. Sc. Phys. et 
Nat. 1868, xxxiii. pp. 5-30. (Abstract) Rep. Br. Assoc. 
Dundee, 1867, Miscell. Comm. p. 97. 
The main features, the author argues, of its nidification are 
determined by the structure and habits of the species, so that a 
nest is delicate and elaborate in proportion to the organization 
of the builder. The materials also of the nest depend in like 
manner on the same properties, and are those which come most 
frequently before the bird^s eyes. But two other causes, or 
factors, must not be neglected ; these are changed conditions 
of existence and the influence of hereditary habit ; and instances 
of both are given. Hence many details of nidification must be 
unintelligible to us as being the results of habit persisting when 
the necessity for it is removed. Mr. Wallace then points out a 
relation existing between the plumage of the hen bird and the 
mode of nidification, and divides nests into two categories accord- 
ing as they conceal or expose the sitting bird, the first containing 
those of all hole-dwellers, purse-Aveavers,and dome-builders, which 
he maintains belong to those of species where the hens are gaily 
or conspicuously coloured ; hence he arrives at the conclusion that 
the kind of nest included in the first category is a consequence of 
this brilliant colouring in the hen, as well as the converse, that 
when the hen is of dull and the cock of bright plumage, the nest 
is open and the sitting bird exposed. In support of this view he 
adduces as examples a great many families ov natui'al groups of 
