The l^EW Species of Brachiopoda, 843 



Orthotropia dolomitica. 



Plate 6, figs. 4-8. 

 Orthotropia dolomitica, Hall. Palaeontology of N. Y., vol. VIII, pt. 2, expl. 

 pi. Ixxxiv, figs. 3-7. 1894. 



Shell known only from internal casts, which are somewhat 

 elongate, biconvex; the pedicle-valve having a prominent and 

 slightly arched umbo, and a distinct, triangular cardinal area. 

 The hinge-line is straight, but shorter than the greatest width of 

 the valves. Both valves are most convex in the umbonal region, 

 and slope to the anterior margin, each with a median sinus. 

 The delthyrium is open ; the muscular impression of the pedicle- 

 valve short, deep and restricted to the rostral region. Its mar- 

 gin is elevated and a short vertical median septum extends from 

 its anterior margin. In the brachial valve the muscular impres- 

 sion is very narrow, also has elevated edges and a median 

 septum. 



Niagara dolomites. JVear Milwaukee, Wisconsin. 



Strophomena Conradi. 



Plate 4, figs. 27-30. 



Strophomena Conradi, Hall. Palaeontology of N. Y., vol. VIII, pt. 1, p. 344, 

 pi. ix a, fig. 3, and pi. xx, figs. 32, 33. 1892. 



Shell semiovate in outline ; hinge-line straight and forming the 

 greatest diameter of the shell.. Cardinal area narrow on both 

 valves ; broader on the pedicle- valve and but slightly elevated at 

 the umbo. Delthyrium covered ; deltidium perforated at the 

 apex. Pedicle-valve convex in the umbonal region, but becoming 

 deeply depressed and concave over the middle of the shell and 

 again elevated about the margins. The depression of the valve 

 is most conspicuous along the median line and on the anterior 

 margin where it produces a subnasute extension. The brachial 

 valve is flat or slightly concave at the umbo, becoming convex 

 over the pallial region ; it reaches its greatest convexity at about 

 the middle of the shell and is thence deflected gradually in the 

 median line and more abruptly on the lateral slopes. 



Surface of the shell covered with radiating strise, arranged in 

 fascicles of 4 to 7 fine ones between each pair of coarser ones. 

 There are no concentric rugae on either valve, but the radiating 

 striae are crossed by exceedingly minute concentric lines. 



