Plate 1 



Figures 



1. Cytherella beyrichoides Swain and Brown, n. sp., lower member of 

 Atkinson Formation, Humble Oil and Refining Company's No. 1 Ben- 

 nett and Langdale well, 3,700-3,710 feet, x 45. 

 Left exterior of holotype shell, U.S.N.M. 132376 

 2a-d. Cytherella austinensis Alexander, lower member of Atkinson Formation, 

 Humble Oil and Refining Company's No. 1 Bennett and Langdale well, 

 3,700-3,710 feet, x 45. 

 2a. Left side of shell, U.S.N.M. 132377 

 2b. Ventral view, U.S.N.M. 132378 

 2c. Left side of shell, U.S.N.M. 132379 

 2d. Interior of right valve, U.S.N.M. 132380 

 3a, b. Cytherella tuberculif era Alexander, upper member of Atkinson Forma- 

 tion, Humble Oil and Refining Company's No. 1 Tindel well, 2,881- 

 2,891 feet, x 45. 

 Left sides of two shells, U.S.N.M. 132381, 132382 

 4a-e. Cytherelloidca ontovariosa Swain and Brown, n. sp., lower member of 

 Atkinson Formation, Humble Oil and Refining Company's No. 1 Ben- 

 nett and Langdale well, 3,700-3,710 feet, x 45. 

 4a. Left side of holotype shell, U.S.N.M. 132383 

 4b. Right side of paratype shell, U.S.N.M. 132384 

 4c. Left side of small paratype, U.S.N.M. 132385 

 4d. Interior of paratype right valve, U.S.N.M. 132386 

 4e. Left side of immature paratype, U.S.N.M. 132387 

 5a-c. Bairdia comanchensis Alexander, lower member of Atkinson Formation, 

 Humble Oil and Refining Company's No. 1 Bennett and Langdale well, 

 3,700-3,710 feet, x 45. 

 5a, b. Right side of two shells, U.S.N.M. 132388, 132389 

 5c. Dorsal view of 5b, U.S.N.M. 132389 

 6. Bairdia ? sp., lower member of Atkinson Formation, Humble Oil and 

 Refining Company's No. 1 Cone well, 3,545-3,556 feet, x 45. 

 Left side of shell, U.S.N.M. 132390 

 7a-c. Paracypris goodlandensis Howe and Laurencich, lower member of Atkin- 

 son Formation, Humble Oil and Refining Company's No. 1 Bennett and 

 Langdale well, 3,700-3,710 feet, x 45. 

 7a, b. Right sides of two shells, U.S.N.M. 132391, 132392 



7c. Ventral view, U.S.N.M. 132393 

 8a, b. Paracypris alta Alexander, lower member of Atkinson Formation, Sun 

 Oil Company's No. 1 Westbury well, 3,834-3,835 feet, x 45. 

 8a. Left side of shell, U.S.N.M. 132394 

 8b. Right side of shell, U.S.N.M. 132395 

 9a, b. Paracypris sp., lower member of Atkinson Formation, Humble Oil and 

 Refining Company's No. 1 Bennett and Langdale well, 3,700-3,710 feet, 

 x 45. 

 9a. Right side of shell, U.S.N.M. 132396 

 9b. Dorsal view, U.S.N.M. 132397 



10. Paracy pride is 1 graysonensis (Alexander), lower member of Atkinson 

 Formation, Humble Oil and Refining Company's No. 1 Bennett and 

 Langdale well, 3,700-3,710 feet, x 45. 

 Right side of shell, U.S.N.M. 132398 

 la.-h. Fossocytheridea lenoirensis Swain and Brown, n. gen., n. sp., beds of 

 Washita age, DuPont water well No. 6, Lenoir County, North Carolina, 

 723-826 feet, x 43. 

 11a. Exterior of immature male paratype right valve, U.S.N.M. 132399 

 lib. Exterior of male paratype right valve, U.S.N.M. 132400 

 lie. Exterior of immature female paratype left valve, U.S.N.M. 132401 

 lid. Right side of holotype female shell, U.S.N.M. 132402 

 lie. Exterior of paratype female right valve, U.S.N.M. 132403 

 llf. Exterior of paratype female left valve, U.S.N.M. 132404 

 llg. Right side of paratype female shell, U.S.N.M. 132405 

 llh. Interior of paratype female left valve, U.S.N.M. 132406 



45 



