1916-17.] The Bone-Cave in the Valley of Allt nan Uamh. 347 
from Discovery Bay (82° N. 65° W.). From this it will be seen that both 
large and small forms occur in the extreme N.E. of North America, 
although their habitat may be 500 miles apart ; and the smaller form lives 
on the most northerly land yet discovered. From what has been said 
above, there appears to be no valid reason for separating the Assynt 
Lemmings specifically from the recent forms, which at present are 
included under the name of D. torquatus. But what about fossil forms ? 
The only fossil Lemming of D. torquatus type which, so far as I know, 
has been recognised and named, is D. gulielmi, and this agrees with D. 
torquatus in the pattern of its teeth, but is said to be distinguished “ by its 
considerably larger size, shorter and broader incisive foramina, broader 
nasals, and heavier teeth.” As we have no skulls from Assynt for com- 
parison, and as the patterns of the teeth are alike, the larger size and 
heavier teeth are the only characters left for comparison, and in these 
particulars the Assynt specimens do not agree with D. gulielmi, the 
alveolar length of the three molars being 8'3 mm. Until better specimens 
are forthcoming, the Assynt Lemming will be referred to Dicrostonyx 
torquatus. 
An incomplete skull of a small Water Vole is most probably referable 
to the black Scottish variety now called Arvicola amphibius reta, Miller ; 
but its horizon and that of a lower front tooth of a Bank Vole ( Evotomys 
glareolus) are uncertain. Jaws of the Field Vole ( Microtus agrestis ) and 
also of Microtus ratticeps have been found in Bed 5. 
Avian remains are numerous and represent several genera and species. 
The bones of Ptarmigan ( Lagopus mutus) are by far the most numerous, 
and the greater number of these are metacarpal and metatarsal bones ; 
among which were a few of larger size which seem to belong to Red- 
grouse (. Lagopus scoticus) ; and it thus appears that at the time these cave 
deposits were accumulating, Ptarmigan were much more abundant than 
Red-grouse in the north of Scotland. Several genera of Ducks have been 
identified, while the Little Auk ( Mergulus alle) and the Puffin ( Fratercula 
arctica) are each represented by a single bone. 
Remains of the Common Frog ( Rana temporaria ) were found in large 
numbers in “ pockets ” in Bed 3, and with them a few bones of the Common 
X. 
Toad ( Bufo vulgaris). A small humerus and one or two other bones agree 
so closely with corresponding parts of the Natter-jack Toad ( Bufo calamita) 
that I have, although with hesitation, included that species in the list. 
Fish vertebrae and portions of skulls occurred in some numbers in Bed 5, 
and belong to either salmon or trout. 
