519 
1862.] Notes of a trip from Simla to the Spiti Valley . 
they are viviporous, one female containing three fceti, though two 
seemed the commoner number. This departure from the plan of 
oviparous reproduction usual among lacertines seems intended to 
meet the exigencies of a severe climate, for in a region where snow 
sometimes falls at midsummer, eggs exposed in the usual manner 
would run considerable risk of having their vitality destroyed by an 
untoward frost. Those naturalists who adopt Darwin’s theory of 
“natural selection,” and the progressive mutation of species, will 
find it an interesting problem to explain (rejecting the old fashioned 
view of creative adaptation I have assumed above) how the oviparous 
progenitors in mythical times of these lizards came to adopt or ac¬ 
quire a viviporous organization, one problem of the many which the 
new developement theory , I should say “ Natural selection' 1 '' raises 
at every step. Near the camp the shores of the lake were perforated 
by the holes of a short-tailed rat or lemming, Vliaiomys leucurus , 
Blyth. Their holes frequently were ranged in a long line against a 
bank and usually extended so far that all attempts to capture an 
animal by digging or flooding the holes with water proved fruitless. 
After infinite trouble, however, I. managed to dig out an adult female, 
which on examination I found to contain six young ones the size of 
horse beans, three in each horn of the uterus. The total length of 
this specimen was 6.15 inches, of which the head was J.80, and the 
tail 1.25. Colour yellowish mouse brown, merging into pale gray 
beneath. This colour, however, only extended to the tips of the hair, 
the body of each hair being dark slaty-blue only visible when the 
fur was thrown back ; fur loose, length, three-eighths of an inch ; 
whiskers, seven-eighths ; ears rounded, medium size, rather oppressed. 
I subsequently got several more, mostly half-grown, by watching 
near their holes with a gun. 
18 th .—Camp a little below halting-place of the 15tli. 
19 thj Ph al any -pair a. —A mere halting-place among loose rocks 
which afford shelter from the wind. A few miles from last night’s 
camp recross the Para river, which here was in several channels, in 
two of which the water nearly reached to a man’s hips. 
20 th, Tatung. —(Tratung Kongma of Cunningham). A mere halt¬ 
ing-place close to the highest limit of furze on the west bank of the 
Para river, a little above where I halted on the 13th. Sleet fell dur- 
