116 PALEONTOLOGY OF KENTUCKY. 



found in great abundance in the hydraulic limestone at the Falls of the Ohio, 

 near Louisville. The figures given by him in said report can not belong to one 

 and the same species ; those marked 2 and 2a are by far too large and robust ; 

 the cardinal view in figure 2 measures, between the cardinal extremities, two 

 and one-fourth inches, while the breadth of euruteines was given by Owen to be 

 one and a half inches. The figures 6, 6<z, 6&, must be taken as the correct 

 representation of Owen's Sp. euruteines. 



Prof. Hall described in Pal. N. Y., volume 4, pages 209, 210 and 211, Sp. 

 euruteines and Sp. euruteines, var. fornacula ; the difference of these consists 

 only in the greater curvature of the cardinal area in fornacula. Owen's side 

 view of euruteines shows the cardinal area considerably concave ; the curvature 

 equal through the whole area from hinge-line to the apex of the beak ; while 

 Hall's side view of euruteines marks the cardinal area as straight, with the 

 exception of a little offset near the beak. Among Hall's figures no side view 

 is given of fornacula ; we are, therefore, left uncertain as to the amount of cur- 

 vature required to place a euruteines among the var. fornacula. The hinge- area 

 in this species is exceedingly variable; in some it is straight, and leans forward, 

 in others it is also straight, but leans backward ; then, again, it leans forward 

 but is curved a little near the beak, while in others it leans backward and is 

 bent either only near the beak or throughout its entire height. Spirifera 

 euruteines is described by Prof. Hall in Pal. N. Y., volume 4, page 209, as 

 follows : 



Shell semi-elliptical ; length and breadth about as six to ten ; hinge-line 

 equal to greatest width of shell. Surface plicate. 



Ventral valve sub -pyramidal, the elevation being nearly equal to half the 

 width, curving abruptly and equally to the front and lateral margins ; the 

 distance from the apex to the cardinal extremity, and to the front of the shell, 

 being about equal. Apex sometimes projecting slightly over the area ; mesial 

 sinus shallow, well defined, and reaching to the apex ; sometimes a little 

 flattened in the bottom. Area extremely elevated, nearly flat or slightly 

 concave above ; fissure large and open to the apex, the length of its sides being 

 about once and a half the width of its base. 



Dorsal valve moderately and evenly convex, with a well defined, low rounded 

 mesial fold ; beak and margin of the valve in the middle slightly arched ; area 

 narrow at the sides, but having the width of a line in the middle. Surface 

 marked by from 16 to 20 plications on each side of the mesial fold or sinus ; 

 these plications are rounded and well defined ; about eight of them reach the 

 apex on the ventral valve, and the remainder coalesce with the angular border 

 of the area. In perfect specimens, the entire surface has been covered by fine 

 concentric undulating striae, which are crossed by fine radiating striae ; the 

 remains of these on some of the silicified specimens give a granulose surface. 



