PLATE Ln— Continued. 



Anoplotheca venusta, Schiuir. 



Fig. 20. The intei ior of a brachial valve, enlarged ; showing the cardinal process and muscular impres- 

 sion. 

 Fig. 21. An internal cast of the pedicle-valve, enlarged ; showing the diductor scars and vascular 



impressions. 

 Figs. 22, 23. Ventral and dorsal views of the exterior. 



Fig. 24. An enlarged view of a specimen showing, by the removal of a ])ortion of the pedicle-valve, the 

 spiral cones, their form and direction. 

 (Figs. 20, 21, 24 are after Sandbbrokr; tigs. 22, 23 after Schnur.) 

 Middle Dev<inian. Eifel, Germany. 



Genus UNCITES, Defrance. 



Page 113. 



Uncites GBYPHUS, Schlotheiui. 



Fig. 25. A specimen from which a portion of the pedicle-valve has been broken, exposing the intei-ior and 

 showing the lateial pouch-shnped expansions of both valves and the incurved beak and crura 

 of the brachial valve. (Davidson.) 



Middle Devonian. Chlmay, Belgium. 

 Fig. 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, Germany. 

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

 delthyrium. (Davidson.) 



Middle Devonian. Chlmay, Belgium. 

 Fig. 28. A dorsal view of a large individual with distorted unciform beak. (F. Roemer.) 



Middle Devonian. Eifel, Germany. 

 Fig. 29. The interior of the umbonal 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. Ti»-quay, England. 



Genus K.4RPINSKIA. Tschernyschew. 



Page 171). 



Karpinskia conjugula, T.sclicniy.sfhow. 



Figs. 30-32. Proiile, dorsal 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 biachial valve. 

 (Tschernyschew.) 



Lower Devonian. Ural Mountains, Russia. 



Subgenus GEUENEWALDTIA. Tschernyschew. 



P.ige 175. 



Gruenewaldtia latilinguis, Schiiur. 



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



(SCHNCH.) 



Middle Devonian. Gerolstein, Germany. 



