PLATE LXX. 



(Figures 1, 2, HI by E. Emmons ; 3, copy.) 



Genus PENTAMERUS, Sowerby. 



I'age -mi. 



Pentamekus oblongus, Sowcrhy. 

 See plales Ixviii, Ixix. 

 Fig. 1. Dorsal view of an internal cast of a broadly ovate shell, with evenly convex valves. 



Niaf^ara dolomites. Near .Vilwaukee, JVisivnshi. 

 Fig. 2. A natural longitudinal section through both valves ; showing the comparatively short median sep- 

 tum and septal jilates, the projecting spondylium and crui-al processes. 

 Clinton group. RocJiesttr, New York. 

 Fig. 3. A copy of the original figure of this species given by Murchi.son in "Silurian System," plate xix, 



figure 10. 

 Fig. A. Dorsal view of a large, elongate-sviliovate shell, with trilobed surface, broadly shouldered um- 

 bones and closely incurved an(i depressed ventral beak. 

 Clinton group. liochtster, New York. 



Pentamerus oblongus, v;ir. subrectus, vai-. iiov. 

 See plates Ixviii, Ixix. 

 Fig. 5. A somewhat weathered specimen in which the valves have been displaced from their normal posi- 

 tion, exposing the spondylium of the pedicle- valve, and, by the removal of the rock, also show- 

 ing a part of the united septal plates of the brachial valve. This spondylioid condition of 

 these plates is a normal feature of this variety. 

 Niagara beds. Jones connty, Iowa. 



Genus CAPP^LLINIA, gen. nov. 



Page 348. 



Capellinia mira, .sp. uov. 



Figs, t), 7. Ventral and cardinal views of an avei'age specimen : showing the i)redominant convexity of the 

 brachial valve, the smooth surface and the position and extent of the interna! plates. 



Fig. 8. Cardinal view of another example in which the convexity and lunbonal incurvature of the Ijrachial 

 \-alve are still more conspicuously developed. 



Fig. 9. Cardinal view of a pedicle-valve ; showing the inconspicuous, suberect beak and wide delthyrium. 



Fig. 10. Ventral view of the same sjiecimen ; showing the length of the median septum. 



Fig. II. Profile view of a normal individual ; showing the relations of the valves. 



Figs. 12, 13. Ventral and profile views of anotner example in which the umbo of the pedicle-valve is ab- 

 ruptly depressed. 



Fig. 14. A brachial valve, showing the length of the septal i)lates and a low radial plication over the uni- 

 bonal region. 



Niagara dolomites. Near Milwaukee, Wiseon.nn. 



