aki a al 
Rev. C. 8. Lyman on the Auroral Bow of June, 1852. 55 
genera is so similar, that they have always been approximated in 
zoological systems, their generic distinctions resting mainly on 
the difference in the structure and form of the teeth. But after 
the discovery in Barmah of Mastodon elephantoides, this distine- 
tion in some measure lost its vale, aud more recently the won- 
derful discoveries of Falconer and Cantley in the Sivalik bills of 
India, seem to have established an almost imperceptible gradation 
from E. nomadicus and Africanus, through E. planifrous, E. in- 
signis, and KE. canesa, in which last the transverse ridges are des- 
uttite of cement, to the different species of Mastodon.* 
The determination of the similarity of form in the brains of 
Se two genera, gives us another important character in which 
they approximate each other, and may suggest the probability 
that future discoveries may result in the breaking down of all 
absolute distinction between them ; though as yet however the 
Seneric boundary is sufficiently well defined in the external forms 
of the heads and some of the details of the skeleton. 
nothing to indicate the precise size of the medulla oblongata ; 
the figure of this portion is therefore ideal. Some indications of 
cerebral and cerebellar convolutions were visible in the ivterior 
of the cranial walls, but too ill defined to warrant any attempt at 
laying them down in the figures. The figures of the Mastodon 
fain are drawn on the scale of one-fourth of an inch to an inch; 
the figure of the Elephant’s brain is reduced from one by Mayer 
in the memoir before referred to. 
cic ee 
= VIL—On the Auroral Bow of June 11th, 1852; by Rev. 
Cuester S. Lyman. 
Observations made upon Auroral Bows by independent ob- 
Servers so situated geographically as to afford reliable data for de- 
termining the height of the phenomenon above the earth, are 
Somewhat rare. And as there exist different opinions among phi- 
ets respecting its usual height, it seems desirable than any 
observations that ‘may throw light on the question should be 
Siven to the public in full. : 
Puan Lo —. 
auna Antiqua Sivalensis, being t logy of the Sivalik Hills in the 
North of India, by Hugh Faved. de, a0! yt Cestien, F.RS, de. 
