Descriptions of New Species and Xew Varieties 219 



Type Locality. Ometopc, Nicaragua. 



Type Material. Collected by B. Shimek in 1893. Four specimens de- 

 posited in United States National ]\luseum, Accession no. 534290. The 

 holotype is shown on plate 134 as fig. 12; figs. 13, 14 are paratypes. 



Tropicorbis shimeki resembles albicans but is smaller, has a greater 

 axial height, and has subcarinate whorls. The parietal lamellae are dis- 

 tinctly shorter and thicker than in other forms of the genus. T. shimeki is 

 smaller than declivis and its axial height is greater; it also has deeper 

 sutures than are found in declivis. 



Additional representatives of T. shimeki were collected by Orcutt in 

 Coatzocoales, Mexico (United States National Museum, Accession no. 

 219696). 



This species is named in honor of Professor B. Shimek. 



GENUS Helisoma 



Helisoma anceps anticostianum, New Variety 



Plate 96, figs. 18-22 



Shell differs from typical anceps in the low axial height, the wide and shal- 

 low spire depression with bluntly angular carina, and the shallow and 

 wide umbilical region of the new variety. The aperture is but slightly 

 expanded. "Whorls about four, evenly and regularly coiled, with faint 



Type Locality. English Bay, Anticosti Island. Quebec, Canada. 



Type Material. Collected by AV. S. Brooks, September 15, 1919. The 

 holotype is shown on plate 96 as fig. 18; paratypes as figs. 19 to 22. De- 

 posited in the collection of the Museum of Comparative Zoology, Harvard 

 University, Accession no. 48285. 



H. anceps anticostianum, a Pleistocene fossil, is similar in appearance 

 to striatinum from ^Milwaukee, but differs in the fact that the new variety 

 has wider and shallower spire depression, has general lower axial height, 

 and lacks distinct angulations above and below. All of these features are 

 marked in striatinum. The whorls are likewise flatter above in the new 

 form than in striatinum. Spiral lines are not notably distinct. Some speci- 

 mens have evidence of a former campanulate lip. 



Helisovna anceps hartschi, New Variety 

 Plate 83, figs. 19-22 



Shell compressed, with four whorls. Periphery rounded. Spire depression 

 wide, a wide cone with flat sides; shallow, bordered by a well defined 

 carina. Base with flattened whorls, the carina sharp and placed near the 

 outer edge. Surface of shell shining, growth lines very fine; occasionally 

 white varices on whorls. Sculpture of very faint spiral lines. Aperture in- 

 verted ear-shaped, forming a sharp V above and a broad V below. Outer 



