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1878. ] Zoology. - 469 
fourteenth day the gills were completely absorbed and the gill- 
clefts absorbed. The remaining larger larve of this experiment 
lost their primary gills less satisfactorily and in a greater length of 
time. New gills began to bud, but the animals were gradually 
destroyed by fungus-growths attacking various parts of their 
skin. The fact that they were altogether more advanced in their 
metamorphosis rendered them unable to adapt themselves 
aquatic life. It was thought from these experiments that the 
spotted and Alpine salamanders were at no very distant period 
of time one species, and that as physical conditions became 
changed one variety became more and more adapted to more ele- 
vated and rocky regions, where water for the early life of the larvæ 
was not commonly to be met with. Thus gradually the birth of 
the young was postponed, and they became terrestrial; concur- 
rently fewer and fewer of the many eggs were developed. The 
spotted salamander, meanwhile, became more and more specialized 
to inhabit the lowland district. The bearings of these facts on 
evolution are of much pertinence. 
Ripeway’s ORNITHOLOGY OF THE FORTIETH PARALLEL.—The 
ornithology, by Mr. R. Ridgway, of the route explored by the 
U. S. Geological Explorations of the Fortieth Parallel, Clarence 
King in charge, has been latély published. e region investi- 
gated lies between Sacramento, Cal., and Salt Lake City, and the 
work is based on field work from June, 1867, to August, 1869, 
inclusive; 769 skins and 753 nests and eggs having been col- 
lected. This is in fact a work on the avifauna of the Great Basin, 
and the subject is discussed under four subdivisions: arboreal, — 
terrestrial, mural and aquatic avifauna. Although the Great 
Basin forms a “natural province of the western region,” Mr. 
Ridgway states that the Sierra Nevada and main Rocky Moun- 
tain Range form “ much less of an actual barrier to the distribu- 
tions of the species than might be supposed,” and he thinks that 
the deserts check the distribution of the species. The author 
shows that Western birds “ have a tendency to extend eastward 
during their fall migrations, thus spreading over the whole of the 
Western Region at this season, though in summer their habitat 
may be confined strictly to the area of Pacific coast drainage.” 
He also discovered that several species supposed to be peculiarly 
eastern, really inhabit the entire breadth of the continent. The 
work is a store-house of novel discoveries regarding the distribu- 
tion and habits of the birds of the Central Province of the United 
