58 CONTENTS OF EACH VOLUME. 
touching the eastern portion of our region en route; others probably find their way 
down to the central tablelands, and a few western species, again, pass over the low 
lands of the Pacific coast. 
Nearly half (636) of the 1413 species enumerated are treated as endemic, fifteen 
of the families—Trochilide, Fringillide, Tanagride, Formicariide, Dendrocolaptide, 
Troglodytide, Turdide, Psittacide, Phasianide, Peristeride, Cotingide, Trogonide, 
Cracide, Tinamide, and Rhamphastide—having many peculiar forms. Compared 
with America north of Mexico, the fauna of the region here dealt with is particularly 
rich, the numbers being, North America (1895) 768 species as against Central 
America 1413; while India (with Ceylon and Burma), with nearly double the area, has 
(1898) only 1626 species. All, or nearly all, the new species were described first in 
the ‘Ibis’ or ‘P. Z. S.’ by Salvin. 
Birds, from their power of flight and the habit of migration common to a large 
number of them, are much more easily distributed than most other vertebrates, and, 
therefore, do not throw the same light on the subject of geographical distribution 
as in the case of more sedentary animals. This must, nevertheless, be applied in 
a general sense, for many of the species are extraordinarily local. 
In dealing with the Aves the limits of the region have been extended to include 
the Revillagigedo Islands on the Pacific side, on account of the numerous sea-birds 
inhabiting them; the Island of Old Providence on the Atlantic side, which has 
a humming-bird peculiar to it; and some places on the Isthmus of Darien. 
The eighty-four coloured plates illustrate 149 species. 
7. Reprivia and Barracuta: by Dr. A. Giinther. 
The author, in his Introduction published in 1902, summarizes his remarks on 
geographical distribution as follows:—The general features of the Reptilian and 
Amphibian Faunas of the area under investigation have been satisfactorily ascertained. 
Forming the connecting link between the two Neogean regions, Central America 
possesses a Reptilian and Batrachian Fauna with the various constituent elements so 
mixed that, if only certain families or genera were taken into consideration, almost 
every district of this area could be associated with either the North- or South-American 
region. ‘The tropical Fauna, as we proceed from lower to higher latitudes, gradually 
changes or is replaced by that of the temperate region; but this change is not 
uniform throughout the breadth of the land, and the two faunas frequently overlap 
in deep and manifold indentations. ‘Tropical types are found to preponderate in 
the low lands of the Atlantic side, which expand into the broad Yucatan peninsula, 
and on the humid slopes of moderate elevation; some extend to, and even reach 
northwards of, the Rio Grande. On the Western side they are found in similar 
localities, but in a narrower belt, along the Pacific coast. On the other hand, 
