6 Bulletin Wisconsin Natural History Society [Vol. 12, Nos. 1 & 2 
the and arboreal as the marten, and aerial as the bats which 
frequent the margins” (he., p. 392). He recognizes animal 
ecological successions as correlated with plant successions. The 
fauna of Isle Royale, as determined by the present geographic 
distribution of the species and varieties of mammals found therein, 
is considered to have northeastern affinities. Adams in his 
investigation did not pay detailed attention to the animal ecology 
of bogs; his studies were of a more general nature; yet they con- 
stitute one of our leading contributions to bog ecology — plant, as 
well as animal. 
The animal ecology of bogs has never been investigated in detail 
and with precision. Shelford (Shelford, 1913) in his recent excel- 
lent work on the ecology of the Chicago region, has rather briefly 
analyzed the animal communities of tamarack swamps, basing his 
studies largely upon the invertebrate fauna of tamarack bogs at 
Mineral Springs, Indiana, and Pistakee Lake, Illinois. Shelford 
classifies the fauna into three groups: (a) the floating bog and 
forest edge association, (b) the tamarack forest formation and 
(c) the pine-birch transition girdle; the tamarack forest formation 
he divides into pools, ground stratum, field stratum, and tree 
stratum. Shelford’s remarks upon the vertebrate fauna, however, 
are largely of a compilatory nature and the number of species 
treated is far from exhaustive. 
From the standpoint of plant ecology bogs have received more 
attention, and, in-as-much as animals are more or less dependent 
upon vegetation and its attendant physical factors and environ- 
ments, these papers have somewhat paved the way for more in- 
tensive study of bog animal ecology. Among the earlier studies 
on American bogs from the standpoint of botanical ecology are 
those of MacMillan (1894) who investigated a peculiar bog for- 
mation (the sphagnum atoll) in central Minnesota. He found 
that the vegetation of the atoll differs from that of the pond 
outside and the inner lagoon. He ascribes the origin of the atolls 
to a season of gradual recession of the waters of the pond fol- 
lowed by a rapid increase in the water level. ‘‘The atolls first 
appeared as annular floating bogs separated from the shoreward 
turf as a result of the original zonal distribution of littoral plants 
and the rise of the waters together with the favorable concur- 
rence of a group of special and necessary conditions. Some of 
