226 The Molluscan Family Planorbidae 



Type Locality. Washington, D. C. 



Type Material. Collected by Foreman, deposited in United States 

 National Museum, Accession no. 124989. Holotype on plate 87 as fig. 13; 

 paratypes as figs. 11 and 12; figs. 14 and 15 of immature shells. 



In addition to the type locality, H. t. marshalli has been identified in 

 collections from various localities in Maryland, New York, New Jersey, 

 and Virginia. 



HelisoTTia campanulatuTn dalli, New Variety 

 Plate 111, fifis. 12. 13, 15, 16 



Shell resembling michiganense in the low axial height, but the body whorl 

 is irregularly coiled and overlaps the penultimate whorl. Five whorls, upper 

 whorls irregular; blunt carina on upper whorls. Four whorls showing on 

 base, base 'reamed out' similar to that of rudentis, and whorls irregular. 

 Umbilicus much smaller than in rudentis and also smaller than in michi- 

 ganense. Lower whorls rounded. Sculpture and aperture as in michiganense. 



Shell Maximum Lesser Aperture Aperture 

 Height Diameter Diameter Height Diameter 



Type Locality. Anticosti Island, Quebec, Canada. 



Type Material. Collected by Dr. J. Schmitt, deposited in United States 

 National Museum, Accession no. 162724. Holotype, plate 111, fig. 12; para- 

 types, figs. 13, 15, 16, five others not figured. 



Differs from other varieties in irregularly coiled body whorl which con- 

 spicuously overlaps the preceding whorls. Base is not excavated, but whorls 

 are irregularly coiled as in spire. Axial height less than in rudentis. 



Helisoma cainponidatu))i dalli is known only from marl deposits. 



Helisoma campanulatum pleistocenicmn, New Variety 

 Plate 110, figs. 21-26 



Shell small, whorls four, the inner spire whorls tightly coiled and gradually 

 increasing in diameter, the last whorl rapidly increasing in diameter. The 

 spire depression occupies about thirty per cent of the greater diameter of 

 the shell while in campanulatum campanidatum it occupies about forty 

 per cent of the greater diameter of the shell. Sutures w^ell impressed. Base 

 with two to two and one-half whorls visible, the whorls tumid. Umbilicus 

 large for the size of the shell. Aperture strongly cami^anulate, the campanu- 

 lation beginning a considerable distance back of the aperture. 



The small diameter of the spire depression and the rapidly enlarging 

 body whorl serve to distinguish this variety from all other forms of 

 campanulatum. This form is distinctly different from the Pleistocene cayn- 

 panidatum of the middle west. 



Type Locality. White Pond, ]\Iarlsboro, Warren Co., New Jersey. 



Type Material. Holotype (figured on plate 110, fig. 21) and eight para- 

 types (five shown on plate 110, figs. 22-26) are in the Lea Collection in 

 the United States National Museum, Accession no. 121195. 



