PLATK XI c— Continued. 



Triplegia Wknlockexsis, Duvidson. 



Fig. 22. A cast of tlie interior of t ho iieiiicli^-valve ; showiii{>' the cai'iiiiial aililiictor iimi iliihictor iniiscuhu' 

 scars anil the imiiressions of the dental lamellne. 

 Wenlock limestone. England. 



Genus MIMULUS, Barrande. 



I'age '272. 



MiMULUs WALDKONEN.SIS, Miller and Dyer. 



Fig. 23. View from the l)rachial valve of a very young- indiviilual. The shell is nearly symmetrical, ami 



shows an open triangular dellhyrium, ending in a circular apical foramen. X S. 

 Fig. 24. The opposite side of the same specimen. X 5. 



(From Memoii-s N. Y. State Museum, Volume I, No. 1, i)late iii, tigs. 9, 9a.) 

 Fig. 2.1. Cardinal view of an adult individual, the type specimen. The cardinal area shows no trace of 



deltidium or foramen. X •^. 

 Figs. 2G, 27, 28. Other views of the same specimen ; showing the peculiar asynunetry of thf shell. 

 Niagara group. Waldron. Indiana. 



MiMULUS contrarius, BiiiTiinde, 



Fig. 29. The exteiior of the jiedicle-viiU'e ; showing the broad median sinus. 



Fig. 30. Cardinal view; showing the relative contour of the valves and the faint trace of the deltidium. 

 Etage Es. Tetiv, Bohemia. 

 (After Barrandb, Systeme Silurieu, Vol. V, pi. 9, tig. vi. A, k.) 



MlMDLUS PERVERSUS, BiVlTJUlde. 



Fig. 31. Dorsal view of the .shell; .showing the sinus on the brachial valve and the Mninlei'ru|iti'cl cardinal 



area of the pedicle-valve. 

 Fig. 32. Cai'dinal view of the same specimen. 



Etage E™. Listice, Bohemia. 

 (After Barrande, Systeme Silurien, Vol. V. jil. 1. tig. iii. <•. e.) 



Genus STREPTIS, Davidson. 



P.ige 274. 



Streptis Grayi, Davidson. 

 Fig. 33. View of a brachial valve which retains the lamellar expansion at one of the growth-lines. X •!. 

 Etage Eo. Lodeaitz, Bohemia. 



(After Bahra.vdk, Systeme Silurien, pi. S3, tig. ii, 3a.) 

 Figs. 34, 3.5. Brachial and anterior views ; showing the asymmetry of the valves, the concentric ornamenta- 

 tion and the perforated deltidium. X 5. 

 Fig. 36. Cardinal view of a similar specimen. X 4. 



Fig. 37. The cardinal process, broken at its tip, jii'obably near the point of bifurcation. 

 Figs. 38, 39. Interiore of pedicle and brachial valves. 



Wenlock limestone. Dudley, England. 

 (After Davidson, Bntish Silurian Brachiopoda, pi. xiii. tigs. l.ia, 176. 1B&, 21. 19. 20.) 



