Explanation of Plate 12 



Figs. 1-2 Jonesina persulcata Croneis and Gale. Dorsum and left valve, x30. Golconda for- 

 mation, loc. 18 



3-5 Oliganisus getsi Croneis and Gutke. 3 left valve. Paint Creek formation, loc. 2, 

 x40 ; 4—5 dorsum and left valve, Renault formation, loc. 12, x30 



6-7 Jonesina tenutstnuosa Cooper, n. sp. Dorsum and left valve. Holotype, x30. Gol- 

 conda formation, loc. 19 p. 57 



8-9 Jonesina intermedia Croneis and Bristol. Dorsum and left valve, x30. Vienna for- 

 mation, loc. 36 p. 56 



10-11 Kloedenella macer Cooper, n. sp. Dorsum and right valve. Holotype, x40. Glen 



Dean formation, loc. 1 p. 57 



12-15 Neokloedenella suhquadrata Croneis and Gutke. Dorsum, left valve, venter and 

 posterior end, x30. Renault formation, loc. 9 



16-17 Jonesina spinigera Cooper, n. sp. Dorsum and left valve, x30. Paint Creek forma- 

 tion, loc. 24 p. 57 



18-19 Lochriella reversa (Morey). Dorsum and left valve, x30. Clore formation, loc. 27 p. 57 



20-21 Jonesina puncta Morey. Dorsum and left valve, x30. Clore formation, loc. 4 . . . p. 56 



22-24 Neokloedenella secunda Croneis and Bristol. Dorsum, left valve, end, x30. Menard 

 formation, loc. 7 



25-27 Perprimitia turrita Croneis and Gutke. Right valve, anterior end and dorsum, x40. 

 Golconda formation, loc. 22 



28-29 Lochriella fenriri (Coryell and Johnson). Dorsum and left valve, x20. Clore forma- 

 tion, loc. 27 p. 57 



30-32 Perprimitia elongata Cooper, n. sp. Right valve, anterior end and dorsum. Holo- 

 type, x40. Paint Creek formation, loc. 2 p. 58 



33-35 Neokloedenella prima Croneis and Funkhouser. Dorsum, left valve and posterior 

 end, x30. Clore formation, loc. 26 



36-38 Perprimitia tenera Cooper, n. sp. Right valve, anterior end and dorsum. Holotype, 



x40. Golconda formation, loc. 19 . . . . p. 58 



39-41 Perprimitia? hicornis Croneis and Gale. Posterior end, dorsum and right valve, x30. 

 Golconda formation, loc. 28 



42-43 Neokloedenella? magna Cooper, n. sp. Dorsum and left valve. Holotype, x30. 



Golconda formation, loc. 19 p. 57 



44-45 Perprimitia funkhouseri Croneis and Thurman. Dorsum and left valve, x40. Kin- 



kaid formation, loc. 28 p. 58 



46-48 Perprimitia robusta Croneis and Gale. Dorsum, left valve and venter, x40. Paint 



Creek formation, loc. 2 p. 58 



49-51 Perprimitia matheri Croneis and Bristol. Dorsum, left and right valves, x40. Vienna 

 formation, loc. 10 



91] 



