PLATE XI c— Continued. 



Triplegia Wenlockensis, Davidson. 



Fig. 22. A cast of the interior of the pedicle-valve ; showing- the cardinal adductor and diductor musculai- 

 scai'S and the impressions of the dental lamellae. 

 Wenlock limestone. England. 



Genus MIMULUS, Barrande. 



Page 272. 



MiMULus Waldeonensis, Miller and Dy&y:. 



Fig. 23. View from the brachial valve of a very young individual. The shell is nearly symmetrical, and 



shows an open triangular delthyiium, ending in a circular apical foramen. X 5. 

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



(From Memoirs N. Y. State Museum, Volume I, No. 1, plate iii, figs. 9, 9a.) 



Fig. 25. Cai'dinal view of an adult individual, the type specimen. The cardinal area shows no trace of 

 deltidium or foi'amen. X 3. 



Figs. 26, 27, 28. Other views of the same specimen ; showing the peculiar asymmetry of the shell. 



Niagara group. Waldron, Indiana. 



^MiMULUs coNTRARius, BaiTaude. 



Fig. 29. The exterior of the pedicle-valve ; showing the broad median sinus. 



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

 Etage Ej. Tethi.. Bohemia. 

 (Aftei' Barrande, Systeme Silurien, Vol. V, pi. 9, tig. vi. A, e.) 



MiMULus PERVERSus, BaiTandc. 



Fig. 31. Dorsal view of the shell ; showing the sinus on the brachial valve and the uninterrupted cardinal 



area of the pedicle-valve. 

 Fig. 32. Cardinal view of the same specimen. 



Etage E2. Listice, Bohemia. 

 (After Barrande, Systeme Silurien, Vol. V, pi. 1, fig. iii, c, e.) 



Genus STREPTIS, Davidson. 



Page 274. 



Streptis Grayi, Davidson. 



Fig. 33. View of a brachial valve which retains the lamellar expansion at one of the growth-lines. X 4. 

 Etage Ea. Lodeiiitz, Bohemia. 



(After Barrande, Systeme Silurien, pi. 83, fig. ii, 3a.) 



Figs. 34, 35. 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, probably near the point of bifurcation. 

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



Wenlock limestone. Dudley, England. 

 (After Davidson, Bntish Silurian Brachiopoda, pi. xiii, figs. 15a, 176, 166, 21, 19, 20.) 



