CRAYFISHES. 381 
along the Ohio shore of Lake Erie from Lucas County, through Ottawa County, 
to Erie and Lorain Counties, from the New York borders of the same Lake in 
Chautauqua and Erie Counties, from the eastern end of Lake Ontario and from 
Lake Oneida; while Ortmann’s discovery of the specimens in the Albany Mu- 
seum from Renssalaer County, N. Y., extends the eastward distribution of this 
crayfish up to Berkshire County, Mass. In the light of all the evidence now col- 
lected it seems to me possible, if not probable, that Berkshire County is the 
eastern limit of the natural distribution of this species and that the discontinuity 
results from imperfect exploration of the waters of New York State. It should 
be noted however, for what it is worth, that the Berkshire countrymen whom I 
have questioned believe the crayfishes are a comparatively late addition to the 
fauna of the Lakes. 
However this may be, there can be no reasonable doubt that the presence 
of this crayfish in Worcester and Middlesex Counties, Mass., and in Lake Winne- 
pesaukee, N. H., is the result of artificial transference at a comparatively recent 
date. The first time this animal was found in Walden Pond, Concord, Middle- 
sex County, Mass., so far as I can learn, was in the summer of 1909, when two 
or more were captured, as I am told by Mr. Reginald Heber Howe, Jr., of the 
Middlesex School, Concord. In 1910 Mr. Howe sent me a fine specimen, a 
male about 33 inches long, which had been taken in the Pond, and in early Octo- 
ber, 1911, the Rev. Smith Owen Dexter and Mr. H. Richardson of Concord 
secured two specimens by a long search under the stones on the edge of Walden. 
Mr. Dexter’s specimen, taken from the Pond the 9th of October, when about 13 
inches long, lived in my aquarium until April 6, 1912, casting its shell twice, 
on February 20 and March 19, and attaining a length of 1finches. On the 14th 
of June, 1912, Mr. Dexter collected four specimens, ranging from 23 to 43 inches 
in length, from the borders of the Pond, and still more during the following 
month. On the 24th of July, 1912, Mr. W. F. Clapp and I got six specimens 
there. iy 
I have been told by citizens of Concord that two men who fished in Walden 
Pond about ten years ago (c. 1903), using crayfishes for bait, threw their surplus 
bait into the Pond and thus unwittingly stocked it with these creatures. 
Walden Pond is apparently a most uncongenial abode for Cambarus immunis, 
being clear as a well and almost destitute of vegetable growth. The favourite 
haunts of this species are rather muddy waters stocked with a rank growth of 
pond weeds. 
In 1913 specimens of this crayfish were collected in Boone Pond, Stow, 
