LEPERDITELLIDAE 



61 



The lateral outline conforms closely to 

 Geisina arcuata (Bean) but since the de- 

 tails of the hingement of Latham's specimen 

 are not certainly known, these thick Gol- 

 conda specimens have been classified as a 

 new species of Sansabella. 



Sansabella tumida Coryell and Sohn 



Plate 13, figures 29-31 



Sansabella tumida Coryell and Sohn, 1938, Jour. 

 Paleontology, vol. 12, p. 599, pi. 69, figs. 4a, b, 

 Reynolds limestone. 



Length, 1.0 mm; height, 0.66 mm; 

 thickness, 0.50 mm. 



Menard formation, locality 20, common. 



The Menard specimens are somewhat 

 larger than those from the Reynolds forma- 

 tion, but agree in form ratio, dorsal and 

 lateral outlines, shape and position of the 

 pit, and small size. 



Sansabella viNiTAENsis (Harlton) 

 Plate 13, figures 44-45 



Jonesina mnitaensis Harlton, 1929, Am. Jour. Scl.. 



ser. 5, vol. 18, p. 260, pi. 1, figs. 7a, b, Fay- 



etteville shale. 

 Jonesina holli Croneis and Gutke, Bull. Denison 



Univ., Jour. Sci. Lab., vol. 34, p. 41, pi. 1, 



figs. 14, 15, Renault formation. 

 Jonesina ivrighti Croneis and Gutke, idem., p. 41, 

 pi. 1, figs. 22, 23, Renault formation. 



Length, 0.67 mm; height, 0.44 mm; 

 thickness, 0.33 mm. 



Renault formation, locality 25, rare. 



Family Leperditellidae 



Ulrich and Bassler 



Genus Cyathus Roth and Skinner 



Cyathus vetustus Cooper, n. sp. 



Plate 13, figures 9-10 



Carapace elongate, tumid, ends rounded ; 

 dorsum and venter broadly curved; hinge 

 area broad, depressed or trough-like for 

 almost entire length, deepest in posterior 

 quarter; articulation cardine, with pro- 

 jection on left valve; surface reticulations 

 fine, in rows subparallel to margins; no pit 

 observed. 



Length, 0.75 mm; height, 0.40 mm; 

 thickness, 0.38 mm. 



Paint Creek formation, locality 2, rare. 



Genus Microparaparchites 

 Croneis and Gale 



Microparaparchites erectus 

 Cooper, n. sp. 



Plate 13, figures 23-25 



Carapace small, short, subovate; dorsum 

 straight, venter strongly convex; ends 

 rounded, posterior one shghtly more acute, 

 with gentle forward swing; spines broad 

 at base, sharply tapering, directed upward 

 and outward slightly toward side; overlap 

 inconspicuous ; surface smooth with slightly 

 punctate area in front of spine just below 

 dorsum. 



Length, 0.50 mm; height, 0.33 mm; 

 thickness, 0.30 mm. 



Golconda formation, locality 19, rare; 

 Vienna formation, locality 10, common; 

 Menard formation, locality 7, common; 

 Clore formation, locality 4, rare. 



M. erectus differs from M. spinosus 

 Croneis and Gale and M. inornatus Croneis 

 and Bristol in the lack of a "hump" or 

 swollen area just in front of the spine. 



Genus Paraparchites Ulrich and Bassler 



Paraparchites cyclopeus (Girty) 



Plate 13, figures 17-19 



Paraparchites nicklesi var. cyclopea Girty, 1910, 

 Ann. New York Acad. Sci., vol. 20, p. 232, 

 no figs., Fayetteville shale. 



Paraparchites robustus Croneis and Gutke, 1939, 

 Bull. Denison Univ., Jour. Sci. Lab., vol. 34, 

 p. 37, pi. 1, fig. 11, Renault formation. 



Carapace large, tumid and ovate ; dorsal 

 shoulder of left valve prominent ; overlap 

 of right valve around entire free margin, 

 greatest along antero-ventral slope ; antero- 

 dorsal spine short ; retral swing moderate ; 

 surface pitted ; greatest height about cen- 

 tral ; greatest length and thickness above 

 middle. 



Length, 1.36 mm; height, 1.02 mm; 

 thickness, 0.71 mm. 



Renault formation, locality 25, common; 

 Golconda formation, locality 18, rare. 



I believe this distinctive form, described 

 by Girty from the Fayetteville shale, merits 

 full specific rank because of the prominent 

 dorsal shoulder on the left valve which 

 Ulrich 's species from the Middle Mississip- 

 pian does not possess. 



