1879. ] A Contribution to the Zoblogy of Montana. 439 
shore of Market lake, Idaho. Twelve miles northward of the latter 
is a much smaller body of clear water which is more permanent 
in its character, since I was told when there that it had not been 
dry since 1871. On the shore I found several specimens of the 
Amblystoma mavortium in various stages of transition from the 
larval condition. They mostly presented stumps of the branchial 
processes, with a greater or less degree of atrophy of the fimbriz. 
These animals occupied holes the size and shape of their bodies 
excavated vertically in the sand, from which their heads pro- 
truded. They were so situated as to be overflowed by every 
slight change of level of the water, which also kept their holes 
full. This situation is especially adapted to a state of transition 
from a branchial to a pulmonary respiration. 
This is the only species of salamander I observed in Montana. 
Its abundance in the central district of the nearctic region is now 
well known, and a full account of its numerous transitional and 
color forms will be found’ in my monograph of the genus Amélv- 
stoma, published in 18672 
Fishes—The food fishes at Fort Benton are the Lucioperca 
orea, the Scaphirhynchops platyrhynchus (sturgeon) and the Lota 
maculosa (ling). Of these the Lucioperca is easily the superior, 
but the sturgeon is not a bad fish. The “chub” of the river at 
that point is the Pogonichthys communis, which sometimes grows 
_ to a foot in length, and is the usual bait for hooks. Ayodon 
tergisus is common there also. In the mountain streams at the 
heads of the Missouri and its tributaries the trout and white-fish 
(Coregonus villiamsonit), are the universally prized pan fishes, I 
heard that the grayling (Thymallus montanus) occurs occasionally 
with them, but did not see it myself. The following is a list of the 
species which I observed in the Missouri river and its tributaries. 
Of course it is a mere contribution to the subject, as I did not 
fish extensively at any point. The larger number of species were 
taken at the lower part of the course of Battle creek, which 
empties into the west side of the Missouri not far north of the 
mouth of the Moreau, Dakota. At the season of the year (Octo- 
ber) when I visited it, the creek was reduced to a chain of pools, 
which occupied hollows in the clay shales of Cretaceous No. 4. 
The alkaline substances from these shales saturated the water, but 
this did not prove fatal to very numerous specimens of eight 
species of fishes. 
Proceedings Academy Natural Sciences, Philadelphia, p. 166. 
