Distribution of Planorbis (Helisoma) Bicarinatus. Say. 111 
years ago by Dr. Edward Palmer (U.S. Nat. Mus. 53,677). 
The National Museum series of this species is an interesting ex- 
hibit of the geographical distribution of this, for a Planorbis, well- 
marked form, as may be seen by the following: 
Without making a list of the several States, Territories or 
localities represented by and included in the museum series and a- 
tested by numerous specimens, a simple geographical outline will 
be indicated by the exterior points herein named, Commencing 
at Cape Elizabeth, Maine, thence westerly, through Lake Simcoe 
Canada, thence to Manitoba! and Winnipeg? lakes, still west- 
erly to Portland,3 Oregon; thence southerly to the Yaqui river 
near Guaymas, Mexico, thence easterly through Kansas, Alabama 
and Georgia, nearly to the Atlantic sea-board by the way of Vir- 
ginia, the Dristrict of Columbia, Pennsylvania, New York and 
Massachusetts to the point first mentioned, Maine! 
Its occurrence at a point so far to the west as Portland, Oregon, 
where Hemphill found it and the extreme southwesterly point on 
the easterly shore of the Gulf of California (Yaqui river), the 
Palmer locality, may be regarded as phenominal. It will now be 
in order for parties who are inclined to make species, apparently 
upon no other ground than the fact of the remoteness of speci- 
mens in hand from the source or habitat of specimens already 
named or as species already described, to halt a little and lend a 
hand to the more useful and higher work of seeking by further 
researches and the accumulation of further geographical data 
to solve the interesting and fundamental problems included in 
the general term, the distribution of species. It would be well 
to observe the substantial hints offered by the Hemphill and 
Palmer locality to collectors to diligently seek whenever 
opportunity occurs for other localities within the territory 
indicated by these extreme outposts of its specific area. 
In the central region the National Museum contains specimens 
from Ft. Stevenson, Dakota and the Yellowstone Park. Its dis- 
tribution to the eastward of these is pretty general and reasonably 
well known, but between these interior localities and the west 
coast, a glance at the map will more clearly impress the reader, 
as it will give a definite idea of the vast extent, of the enormous 
area that offers an ample reward to the field worker not only as 
to this species, but who can say as to how many others. 
Not many years ago without doubt, these west coast speci- 
mens would have been honored with a specific title, for the mat- 
ter of distribution was seldom considered. The great high-way 
furnished by the Colorado of the West, the extensive drainage 
system of which said river is the main channel includes no doubt 
within its northerly limits the source or scources from which the 
colony detected by Dr. Palmer, the first settlers we may call them 
migrated. Not one by one grand leap or by a single and direct 
1—Collected by Miller Christy; 2—teste Bell; 3—H. Hemphill. 
