INSTITUTE OF SCIENCE, PHILADELPHIA. 105 



FOSSILS OF THE SILEX-BEABING MABL (MIOCENE) OF 

 BALLAST POINT, HILLSBOBO BAY. 



GASTEROPODA. 



Genus WAGNERIA, Heilprin. 



I propose this genus for a very remarkable shell, distinguished by 

 peculiarities of structure which broadly separate it from all other Gaste- 

 ropoda. These peculiarities are : firstly, that the inner or columellar lip 

 is so largely developed as to cause it to envelop a very large, if not the 

 greater, part of the shell, duplicating the outer wall and labrum ; and 

 secondly, that through an apparent conjunction of both folds of the 

 mantle, a dome of shell is built over the spire, from which its own walls 

 are separated by a free air-space. This part of the shell appears, there- 

 fore, as a second section, completely separated from the basal or apertural 

 division. In what precise manner this dome was formed it is impossible 

 to say, but manifestly the lobes of the mantle must have extended upward 

 from the aperture, arched over, and deposited the shell-layer. The free 

 space which separates the dome from the spire would seem to indicate 

 that the mantle possessed a special rigidity, by which it retained itself. 

 The genus may be briefly characterized as follows : 



Shell irregularly oval or rounded-fusiform, intumescently knobbed ; 

 spire elevated, broadly scalariform, concealed in a pointed dome which is 

 formed over it by a free upward extension of both lobes of the mantle ; 

 aperture narrow, deflected forward in its upper course, where it is reduced 

 to a mere slit, appressed to the body of the shell by a pseudalar expan- 

 sion of the outer lip ; inner lip developed to a most extraordinary extent, 

 covering by its expansion almost the entire, or the whole, shell, duplicating 

 the outer lip. 



This extraordinary genus of shells, which I take pleasure in naming 

 after the late Prof. William Wagner, the generous founder of the Wagner 

 Free Institute of Science, of this city, is apparently a near ally of Orthaulax 

 of Gabb (Proc. Acad. Nat. Sciences Phila., 1872, p. 272, pi. ix, figs. 3, 4; 

 Trans. Am. Phil. Soc., xv, p. 234), a form evidently closely related to some 

 of the Rostellariae, as Calyptrophorus and Hippochrenes (Macroptera), in 

 which the inner lip is frequently abnormally developed. The remarkable 

 duplication seen in Wagneria, produced by the complete backward pro- 

 longation of the labium, which actually overlaps a large, if not the greater, 



