Netu Species of Devonian Fossils. 133 



and differs distinctly in its truncated anterior margin and in the 

 absence of a fold and sinus. 



Occurrence: Birdsong shale, the single known specimen being 

 found at the Swayne's mill locality near the mouth of Big Sandy 

 River. 



Wilsonia wadei, n. sp. 

 Plate III, figs. 3, 4 



Description: Shell small, subglobular or subpentahedral in 

 form; deepest and strongly truncate at the front margin; length, 

 breadth, and height about equal. Ventral valve depressed con- 

 vex, but sharply deflected, almost angulated along the margins ; 

 beak short and small, neatly incurved. A mesial sinus begins 

 about the middle of the valve and is produced anteriorly into a 

 narrow linguiform extension that is sharply deflected at right 

 angles to the plane of the valve. Dorsal valve about as deep as 

 the ventral, also gently convex and steeply angulated at the 

 margins. A fold on the anterior portion corresponds to the sinus 

 of the opposite valve. The surface bears low rounded plications, 

 of which one occupies the sinus, two the fold, and three each 

 lateral slope. Rarely in large specimens there are two plications 

 on the sinus and three on the fold. The plications become obso- 

 lescent near the beak. 



Internally the hinge-plate in the dorsal valve bears a crural 

 cavity as in Camarotoechia, and the cardinal process is wanting. 



Dimensions: Length, 9 mm. ; width, 9 mm. ; height, 8.5 mm. 

 Of a large specimen: 11 mm., 10.5 mm., and 9.2 mm. respec- 

 tively. 



Occurrence: Common in the Birdsong shale and less abundant 

 in the Ross limestone at Grandview, Perryville, Big Lick Creek, 

 Birdsong Creek, etc. 



Uncinulus lindenensis, n. sp. 

 Plate III, figs. 5, 6 

 Description: Shell of medium size, subpentahedral in form, 

 subtriangular to subpentagonal in outline, as wide as or wider 

 than long. Ventral valve almost flat, shallow and steeply angu- 

 lated at the margins. A flat shallow sinus is visible only near 

 the anterior margin, where it is produced into a very long 



