THE GENERAL SUBJECT. 
21 
Hutton, F. W. 
Laridoi.'] 
Kirby, W. F. 
(loc. cit.)y and criticizes the Opinions of Dr. Pettigrew (Zool. 
llec. V. p. 38). y 
On the flight of the Blaek-backed Gull.|^ [See 
On the Geographical Distribution of the 
Diurnal Lepidoptera as compared with that of Birds. J. L. S. 
, Zool. xi. pp. 43 1-439. 
( The author bases his remarks on the old estimate of 7500 
species of Birds, though admitting that 11,000 have now been 
enumerated, while with regard to Butterflies he takes his own 
recent estimate of 7700 speeies") the results therefore are hardly 
satisfaetory, 
/Marsh, O. C. Notice of some new fossil Mammals and Birds 
from the Tertiary formation of the West. Am. J. Sc. (3) 
ii. pp. 120-127. [Falconidce, StrigideSj PhasianidaE.'] 
I . Preliminary description of Hesperornis regalis, with 
notices of some other new species of Cretaceous Birds. Op, 
cit. iii. pp. 360-365. \^8colopacid(Sj PelecanidcBj Colymhid(s.'] 
^ . Notice of some new Tertiary and Post-tertiary Birds. 
Op. cit. iv. pp. 256-262. [Picarimy GrallcCy Gruida, Alcid^y 
SaururcB.'] 
^ Preen, C. Ausrottung der Singvogel. J. f. O. 1872, pp. 209- 
224, 275-286. 
( Discusses very-ably the causes which in Germany affect the 
abundance of song-birds, showing that decrease in their numbers 
is the effect of physical causes and not of direct human agency, 
the consequences of which are scarcely appreciably 
^SuNDEVALL, Carl J. Mctliodi Naturalis Avium disponeudarum 
Tentamen. 8vo. Stockholm: 1872-73, pp. a-f, Ixix, 
187, ll*t 
Without expressing an opinion as to whether the author has 
found the natural system for which he has been searching, no 
doubt can exist as to the importance of this unpretending little 
tract. QTf ter a short Preface (pp. c-f) comes an Introduction 
(pp. i-xxxiv), in which many subjects highly interesting to the 
general naturalist are discussed, as will be seen from the head- 
ings of the chapters into which it is divided: — 1. Remarks bn 
the growth of the Ornithological System (pp. i-vii) ; 2. On the 
idea of Affinity as the ground of a Natural System (pp. viii-xv) ; 
3. On the object of Systematic Exposition (pp. xv-xx) ; 4. Re- 
marks on the Arrangement here admitted (pp. xx-xxiv) ; and 
5. On Systematic Names (pp. xxiv-xxxiii) . Both Preface and 
( t Properly only the former part (^pp. i-xlviii, 1-72) of this work belongs 
to the literature of 1872 ; but, to obviate the need of reclining to it, the latter 
part is noticed here as well, though, owing to the author’s ill health, not 
published till 1873. The latter part contains several corrections, the effects 
of which are incorporated in our abstract.^ 
