PLATE 61 



Pholidops ovata Hall 

 Page 228. 



Figs. 1, 2. Interior moulds of two dorsal valves. 



Rhi pidomella emarginata Hall 

 Page 23J. 



Fig. 3. Exterior view of pedicle valve. 



Figs. 4, 5. Exterior views of two brachial valves. 



Rhipidomella musculosa Hall 

 Page 230. 



Fig. 6. Exterior view of pedicle-valve. 



Fig. 7. Exterior view of a pedicle valve showing the large, fan-shaped muscular im- 

 pressions. 

 Fig. 8. Brachial valve of larger individual. 



Dalmanella lenticularis (Vanuxem) 

 Page 229. 



Fig. 9. Partly exfoliated brachial valve. 



Figs. 10, 11. Exterior views of two pedicle valves. 



Dalmanella oriskania sp. nov. 

 Page 229. 



Fig. 12. Exterior view of brachial valve. 



Fig. 13. Mould of the interior of a brachial valve, showing the form of the muscular 



impressions. 

 Fig. 14. Exterior view of a pedicle valve. 



Leptaena ventricosa (Hall) 

 Page 231. 



Fig. 15. Partly exfoliated pedicle valve, showing muscular imprints. 

 Fig. 16. Exterior view of pedicle valve. 

 Fig. 17. Exterior view of brachial valve. 



Stropheodonta cf. demissa (Conrad) 

 Page 232. 



Fig. 18. Exterior view of a brachial valve. 



Stropheodonta cf. inequiradiata Hall 

 Page 233. 



Figs. 19, 20. Views of two pedicle valves. 



Stropheodonta missouriensis sp. nov. 

 Page 232. 



Fig. 21. Interior view of a brachial valve. 



Fig. 22. Interior view of an incomplete brachial valve, showing muscular impressions. 



