402 THE CHICAGO ACADEMY OF SCIENCES. 
Jaw, Raputa and GeniraLiA: Unknown. 
Rance: Maine. A species of the Alleghanian division of the 
Transition life zone and of the Nova Scotian region. As the species 
has been so misunderstood and mixed with catascopium, apicina, etc., 
only those records are mapped which are known to be correct. No 
authentic records are known outside of the state of Maine. The Con- 
necticut record of Linsley and the British American references by 
Bell and Whiteaves are believed to have been based on some form of 
catascopium. ; 
RECORDS. 
Marne: Winnecook Lake, Waldo Co. (Berry); Maine (Anthony; Binney; 
Griffith; Haldeman; Lea; Lewis; Mighels; Walker) ; Portland, Cumberland Co. 
(Chickering) ; Unity, Waldo Co. (Adams; Mighels). 
GEOLOGICAL DIsTRIBUTION: Unknown. . 
Hasitat: ‘Adhering to boulders just below the surface of the 
water.” (Chambers). 
Remarks: Decollata is a very distinctive species, easily known 
by its flatly sloping spire, tumid body whorl, somewhat patulous aper- 
ture and very tightly closed umbilicus. It does not seem to be similar 
to any species, excepting, perhaps, some short-spired forms of cat- 
ascopium which, however, have a differently shaped spire, aperture 
and umbilical region. The spire is decollated in a majority of the 
specimens examined. 
Decollata seems to be little understood by most conchologists. It 
has been placed in both catascopium and emarginata, and has also been 
considered a variety of mighelsi. Specimens of apicina from northern 
Michigan and Lake Superior have been identified as decollata and 
specimens of emarginata angulata have also been so identified. This 
confusion has arisen from lack of authentic specimens for comparison. 
The specimen figured by Binney (fig. 37, ex Haldeman, Smith, No. 
9132) is larger and much thinner than specimens believed to be typical. 
This specimen measures as follows: Length, 21.00; breadth, 15.00; 
aperture length, 14.00; breadth 10.00 mill. Mighel’s original measure- 
ments are: length, 15.00; breadth, 12.50 mill. This specimen has all 
of the characteristics of decollata excepting that it is larger, thinner and 
has a more patulous aperture. It is not mighelsi, as may be seen by 
comparing the spire and body whorl with those of mighelsi, which are 
much broader, rounder and of a different shape (compare Binney’s 
figure with figure 9 on plate XLI). Specimens in the Boston Society 
of Natural History (No. 24192) which were deposited by Mighels 
and may, indeed, be considered cotypes, agree well with Binney’s 
figure 37. Two of these are figured on plate XLI, figures 8 ond 9. 
