PLATE Ln— Conttnaed. 



Anoplotheca venusta, Schmir. 



Fig. 20. The int«iior of a brachial valve, enlarged; showing the cardinal process and muscular impres- 

 sion. 

 Tig. 31. An internal cast of the pedicle-valve, enlarged ; showing the diductor scars and vascular 



impressions. 

 Ftga. SS, 23. Ventral and dorsal views of the exterior. 



Pig. 34. An enlarged view of a specimen showing, by the removal of a portion of the pedicle-valve, the 

 spiral cones, their form nnd dii-ection. 

 (Pigs. 20, 21, 24 are after SANPBBRrjKR ; tigs. 22, 23 after Schndr.) 

 Middle Devonian. Eifel, Gemuiny. 



Genus UNCITES, Defrance. 



Page 118. 



Uncites GBYPHU8, Schlotheiui. 



Pig. 26. A specimen from which a portion of the pedicle-valve has been broken, exposing the interior and 

 showing the lateral pouch-shaped expansions of both valves and the incurved beak and crura 

 of the brachial valve. (Davidsom.) 



Middle Devonian. Chimay, Belgium. 

 Pig. 26. A profile of a specimen retaining both valves ; showing their convexity, and the prolongation of 

 the beak of the pedicle- valve. (Davidson.) 



Middle Devonian. Paffrath, Oermany. 

 Fig. '27. A dorsal view of a medium-sized specimen ; showing the character of the exterior and the deep 

 dellhyrium. (Davidson.) 



Middle Devonian. Chimay, Belgium. 

 Pig. 28. A dorsal view of a large individual with distorted unciform beak. (P. Robmbr.) 



Middle Devonian. Eifel, Qennany. 

 Fig. 29. The interior of the umhonal region of the brachial valve, enlarged; showing the hinge-plate, 

 lateral pouches, and grooved ridges extending forward from the base of the hinge-plate. 

 (Davidson.) 



Middle Devonian. Torquay, England. 



Genus KARPINSKIA, Tschernyschew. 



Page 176. 



Karpinskia conjugula, Tschernyschew. 



Figs. 30-32. Profile, doi-sal and ventral views of the exterior of conjoined valves. 



Fig. 33. A transverse section ; showing the form of the spiral cones and their convergence into the cavity 

 of the brachial valve. 



(TSCHERNTSCHBW.) 



Lower Devonian. Ural Mountains, Russia. 



Subgenus GRUENEWALDTIA, Tschernyschew. 



I'age 176. 



Gruenewaldtia LATILINGUI8, Schiiur. 

 Figs. 34-36. Dorsal, profile and frontal views ; showing the contour and exterior markings of the species. 



(SCHMIIB.) 



Middle Devonian. Oerolatein, Oermany. 



