GENUS VITULINA. 
411 
Surface covered by minute papillas. Substance finely punctate. 
In the interior of the ventral valve, the margins of the foramen are 
extended in two strong teeth, which are supported on the lower and 
lateral margins by a callosity of the shell. Beneath the apex, a strong 
callosity or false area extends across the valve and reaches to the base 
of the teeth. This callosity is visible in the foramen, and from its lower 
margin proceeds a slender median septum (fig. 1 h). On each side of this 
septum, at its junction with the transverse callosity, there is a small 
pit for the occlusor muscle; and beyond this a broad flabelliform area 
for the divaricator muscular attachments. These features are shown in 
the cast, fig. 1 i. 
In the dorsal valve, there is a strong median ridge'"or septum which 
terminates in a slightly lobed cardinal process; on each side of this are 
the crural processes, and between these and the margin are the teeth 
sockets. 
Figures 1 a, 5, are of the largest specimens observed. Figures 1 c and 1 d are enlarged, 
showing the character of the plications and the pustulose surface. Figures 1 e, f are 
enlargements from an entire specimen : the profile, as given, represents the dorsal area as 
proportionally too wide. The interiors of the valves and the cast of the ventral valve are 
enlarged two diameters. 
Geological formation and localities. This species was first observed in a single 
individual among specimens collected at Canandaigua lake, and was afterwards 
found at York in Livingston county. More recently, and since the engravings 
were completed, Mr. Whitfield has found the fossil in considerable numbers 
near Tully and at Tinker’s falls in Onondaga county. 
