1894] NATURAL SCIENCES OF PHILADELPHIA. 17 



gina; and this is the most important generic character. In PI. I, fig. 

 4, is shown the dart of G. llgem, magnified twelve diameters. 



There are strong reasons for believing that the presence of a dart, 

 the coronal glands being correlated with it, is a very old character in 

 Zoii!tid<e, and that it was present in the nndifterentiated stock from 

 wliich nearly all the existing genera have diverged. ' It this be true, 

 then Vltrea, Omphalina, etc., must be regarded as secondarily haplo- 

 gonous, having lost the dart apparatus which was present in their 

 ancestors. 



G. suppressa Say. 



Gettysburg, Adams County, Pa., 64,083. Monterey, Franklin 

 County, Pa., 64,087. Also at York Furnace, York County, Pa. 

 (Witmer Stone). In Maryland at Cave Town, 64,084, and Sum- 

 rait of North Mountain, 64,080; Martin's Mountain, 64,680, between 

 Green and Polish Mts., 64,682. Cumberland, Allegheny Co., 64,685, 

 and Morgan Co., ^V. Va., opposite Hancock, 64,681. 



G. ligera Say. 



All of the specimens were small, shining and smoother than usual, 

 measuring about 11 mm. in diameter, the umbilical perforation 

 minute, about -3 mm. wide. Gettysburg, Pa., 64,697. Chewsville, 

 Washington Co., Md., 64,690. Ten miles west of Hancock, Md., 

 64,689;" Cumberland, Allegheny Co., Md., 64,688. 



Family ENDODONTIDJE. 



Genus PYRAMIDULA Fitzinger. 



The generic names used in this paper for Helices are fully ex- 

 plained in the writer's guide to the Helices, now^ being published. 



P. alternata Say. 



Chewsville, Washington Co., Md., 64,698. Martin's :Mountain, 

 Md., 64,699, 64,700. West Virginia, opposite Hancock, Md. 

 Cumberland, Md., 64,697. Collected by Stone at York Furnace, 

 York Co., Pa. 



P. striatella Aiitli. 



Hanover, York Co., Pa., 64,703. A delicate, fine-ribbed form. 



1 Perhaps excepting Contilus, Microcystis, etc. 



