CRAYFISHES. 381 



along the Ohio shore of Lake Erie from Lucas County, through Ottawa County, 

 to Erie and Lorain Counties, from the New York jjorders 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 Berksliire 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 3| 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 

 secm'ed 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 1? 

 inches long, lived in my aquarium until April 0, 1912, casting its shell twice, 

 on February 20 and March 19, and attaining a length of if inches. On the 14th 

 of June, 1912, Mr. Dexter collected four specimens, ranging from 2| to 4^ 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. 



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, throw theii- surplus 

 bait into the Pond and thus unwittingly stocked it with these creatures. 



Walden Pond is apparently a most uncongenial abode for Camharus immunis, 

 being clear as a well and almost destitute of vegetable growth. The fa\-ourite 

 haunts of this species are rather muddy waters stocked with a rank growth of 

 pond weeds. 



In 1913 specimens of this craj^fish were collected in Boone Pond, Stow, 



