136 
Aug. F. Foerste 
concrete bridge crossing the railroad from Versailles to Frank- 
fort, and approximately 20 feet above the Strophomena vicina 
horizon. In the brachial valve of these specimens there is a 
very narrow and very low median septum. In a specimen 18 
mm. in length, this septum is most distinct 11 mm. from the 
beak. A small obliquely-oval muscular scar is found on each 
side of the septum. The inner edges of these scars are about half 
a millimeter distant from the median septum, and lengthwise 
they extend from 9 to 10.5 mm. from the beak. Their longest 
diameter is directed toward the antero-lateral outlines of the 
shell. They represent, apparently, the central scars at the ante- 
rior end of the concrete lateral areas, but there is no trace of 
semi-elliptical concrete laterals, crossed diagonally by subparal- 
lel striae, as figured by Hall and Clarke in the case of Lingula 
procteri, although specimens showing the interiors of the brachial 
valves are not rare. Anteriorly, the median septum can be 
traced in a much fainter form as far as 13.5 mm. from the beak. 
This part of the septum separates the rather narrow anterior 
lateral scars. In the interior of the pedicel valve, there are two 
very narrow and very shallow grooves, limiting the very low and 
broad median septum. At a distance of 8 or 9 mm. from the 
beak, this septum attains a width of about four-fifths of a milli- 
meter, and in some specimens only two-thirds of a millimeter. 
There is no trace of any other structure. These probably are 
the specimens to which Ulrich refers in his original description of 
Lingula procteri, when he states that this species ranges from the 
middle beds of the Trenton in central Kentucky to about 50 
feet above low-water mark in the Ohio River at Covington, Ken- 
tucky. Considering the fact that most species of Lingula have 
been erected upon variations in the outline of the shell and upon 
the surface ornamentation, the proposal of a new name based 
upon interior characteristics can not expect to find welcome; 
nevertheless, if the discrimination proves an accurate one, it 
must stand. Science can not profit by the failure to discriminate 
between Lingula procteri and Lingula versaillesensis, if the dis- 
tinctions here pointed out prove to be constant and to belong 
to different horizons 
The shell substance oi Lingula 'bersaillesensish very white. The 
exterior is nearly smooth, and i^ ornamented by very faint, con- 
centric, broad, flat striations. There is no trace of radiate lines 
