Notes on Cincinnatian Fossil Types 
307 
median septum is indicated by the type of Lingula vanhornei. Here 
the concrete laterals are rather weakly defined, and their anterior 
margin extends to a distance of nearly 11 millimeters from the 
beak, the entire length of this brachial valve being 17 millimeters. 
Between these concrete laterals there is an ill-defined linear space, 
about half a millimeter in width anteriorly, obscurely elevated at the 
lateral margins, and this linear space extends anterior to the concrete 
laterals as far as the anterior part of the vascular trunks, of Hall 
and Clarke. These vascular trunks are within 1.5 mm. from the 
margin of the shell at a distance of 11 mm. from the beak, and curve 
around anteriorly so as to reach within 1.7 mm. of the front margin 
of the shell. In their curvature, these vascular trunks of Lingula 
vanhornei closely resemble those of Lingula elderi, as figured by Hall 
and Clarke. Faint traces of vascular branches extend from the 
vascular trunks toward the antero-lateral and anterior margins of 
the shell, as in Lingula elderi, but there are no traces of vascular 
branches extending from the vascular trunks toward the concrete 
laterals. 
The general shape of the muscular area of the pedicel valve of 
Lingula vanhornei also is similar to that of Lingula procteri. In 
general this shape may be defined as broadly cuneate with a very 
divergent V-shaped anterior margin along which the interior of the 
shell is moderately thickened and from which radiate vascular 
branches. The narrow, almost linear area, between the concrete 
laterals forming the major part of this muscular area, is not clearly 
defined. The vascular trunks of the pedicel valve pursue essentially 
the same directions as those of the brachial valve, and from these 
trunks the vascular branches may be traced toward the antero- 
lateral and anterior margins of the shell, but the vascular branches 
between these vascular trunks and the anterior margin of the con- 
crete laterals appear to radiate from the anterior margin of the 
latter toward the vascular trunks, of Hall and Clarke, and do not 
appear to have their origin in these trunks and to extend from the 
• trunks toward the concrete laterals, as in the figures presented by 
these authors in the case of Lingula elderi. 
The length of the type is 18 mm. the beak of the pedicel valve 
extends almost a millimeter anterior to that of the brachial valve. 
The width of the shell is 11 mm. The thickness from valve to valve 
is 4.5 mm. The outline is oval oblong. The type was found at 
Versailles, Indiana, and probably came from the Waynesville member 
