PALEONTOLOGY 



FIG. 7 VARIOUS BRACHIOPODS. 



a, a', Obolus appolinis Eichwald, Cambrian, ventral, and dorsal valves : 

 below the umbo in each is the cardinal area (shaded), that of the 

 ventral valve having a median pedicle-groove ; muscle-impressions in 

 outline. (Natural size.) 6, b' , Lingula anatina Bruguiere, Recent, 

 ventral, and dorsal valves: parts as" in a, a', (xj.) c, c 1 , Dis- 

 cinisca lamellosa Broderip, Recent, ventral, and side views. Fora- 

 men black. (Natural size.) d, d' , Dalinanclla \Orthis\ elegantula 

 (Dalman), Silurian, ventral, and dorsal valves : muscle-impressions 

 shaded, (xf.) e, e', Productus semireticuiatus (Martin), Lower 

 Carboniferous, dorsal view, and interior of dorsal valve. (x. ) 

 f, g, Umbonal views of ventral valves of f, Schellwienella ; g, Derby a; 

 areas shaded, dental plates (black) showng through the test, h, Um- 



