58 
ZOOLOGICAL LITERATURE. 
grounding his opinion chiefly on the fact of the luemhers of the 
genus Chionis and of the yellow-hooded group of EudypUs being 
confined within that limit. Herr von Pelzeln includes also some 
general remarks on the changes and variations observed in the 
plumage of many of the Falconid(By which have since been ex- 
tended and contributed to another publication. (They are further 
noticed under the heading Pterylography.^^) He has also some 
remarks on the geographical distribution of Accipitres, The 
new species described are Micrastur macrorhynchus y Gerygone 
aucklandicuy Mecistura swinhoiiy Volvocivora schierbrandiy Car- 
pophaga frauenfeldiy and Aramides zelebori ; but observations on 
upwards of 700 species of all orders and from all regions (exclu- 
sive of those mentioned in the pterylological dissertation) are in- 
troduced^ which alone makes the work one of great importance. 
The true habitats of several rare birds are now for the first time 
determined with precision, and the eggs of sixteen species are 
figured. [Cf. Ibis, 1866, pp. 115, 116.) 
'^PucHERAN, — . Indications que pent fournir la Geologic pour 
Pexplication dcs diflercnces que presentent les Faunes 
actuelles. Eev. et Mag. de Zoologie, 1865, pp. 9-15, 33-40, 
65-74, 97-115, 161-170, 193-197, 225-240, 289-295. 
This series of papers (still, so far as we know, unfinished) is 
in the form of a letter to Prof. d^Archiac ; and from the well- 
known reputation of the author as an ornithologist, the fact 
may be at once inferred that a great many of his inferences are 
drfiwn from the class Aves. The first question to which Dr. 
Pucheran turns his attention is to decide whether the harmony 
existing between Desert-species and the places they occupy 
has been pre-established or post-established. Finding (1) that 
the Great African Desert is by geology proved to have been an 
^rm of the sea, and (2) that the forms inhabiting it are repre- 
sented in the bordering districts by others only a little differing 
jn coloration, he comes to the conclusion that the harmony is 
post-established. The next question is as to the mode whereby 
this harmony, which in birds seems confined to coloration, is 
produced ; and the author appears to consider contact with the 
soil a sufficient cause, though one particular case which he cites, 
that of the rufescence of specimens of Gypaetus fi’om Algeria 
{cf. Ibis, 1859, p. 85, and F. W. Meves in CEfvers. Yet.-Akad, 
Forh. Stockholm, xvii. p. 487), shows that the change of hue 
thus acquired is merely superficial, and therefore not really in 
point. Dr. Pucheran then proceeds to enter upon the subject 
of the distribution of species, and propounds the question as to the 
basis that should justify a zoologist in considering any particular 
region to possess a special fauna. On this point he is of opinion 
that mere differences of species are insufficient, but that diffe^’- 
ences of genera, if not of families, are required; and accordingly 
