KLOEDENELLIDAE 



59 



and lobe along the ventral margin low and 

 somewhat indistinct; sulcus about central, 

 quite deep; greatest height anterior, thick- 

 ness posterior, length above midheight. 



Length, 0.46 mm; height, 0.27 mm; 

 thickness, 0.24 mm. 



Golconda formation, locality 19, rare; 

 Glen Dean formation, locality 23, rare. 



The lack of posterior obesity marks the 

 figured specimen as a male. 



Genus Sansabella Roundy* 



Sansabella ampla Cooper, n. sp. 



Plate 13, figures 32-35 



Carapace large, ovate, with subparallel 

 dorsum and venter ; ends broadly rounded ; 

 forward swing very slight ; hinge five-eighths 

 of total shell length straight, channeled, 

 terminated by a notch at each end; sulcus 

 narrow in lower part, widening into car- 

 dinal area; overlap very prominent around 

 posterior and ventral free margins ; greatest 

 thickness and height of female posterior, 

 greatest thickness of male central; greatest 

 length central; surface smooth. 



Length, 1.07 mm; height, 0.67 mm; 

 thickness, 0.53 mm. 



Paint Creek formation, locality 2, com- 

 mon. 



Sansabella bradfieldi 

 (Coryell and Sohn) 

 Plate 13, figures 46-51 



Persansahella bradfieldi Coryell and Sohn, 1938, 

 Jour. Paleontology, vol. 12, p. 598, pi. 69, 

 figs. 2a, b, Reynolds limestone. 



Sansabella ivhitei Coryell and Sohn (not Brad- 

 field), idem., p. 599, pi. 69, fig. 3, Reynolds 

 limestone. 



Jonesina? skinneri (not J.f dubia) Croneis and 

 Gale, 1938, Bull. Denison Univ., Jour. Scl. 

 Lab., vol. 33, p. 265, pi. 5, fig. 29, Golconda 

 formation. 



Sansabella joJinsoni (not S. lae'vis) Croneis and 

 Thurman 1938, Bull. Denison Univ., jour. 

 Sci. Lab., vol. 33, p. 302, pi. 7, figs. 13, 14, 

 Kinkaid formation. — Croneis and Bristol, 

 1939, ibid., vol. 34, p. 70, pi. 3, figs. 5-7, 

 Menard formation. 



Carapace subrhomboidal, overlap around 

 free margin, especially prominent along 

 venter, dorsum straight ; sinus deep, 

 elongate vertically, extending from mid- 



*See discussion of Sansabella under Jonesina, p. 55; 

 also under Lochriclla, p. 57. 



height almost to dorsum; forward swing 

 distinct; hinge deeply channeled, straight; 

 dorsal outline wedge-shaped due to obesity 

 of posterior half; surface smooth. 



Length, 0,80 mm; height, 0.51 mm; 

 thickness, 0.41 mm, 



Golconda formation, localities 22 (rare) 

 and 19 (common) ; Glen Dean formation, 

 locality 1, rare; Menard formation, locali- 

 ties 7 (rare) and 28 (common) ; Kinkaid 

 formation, locality 5, rare. 



These upper Chester forms, described 

 under various names, are so similar that 

 they are practically indistinguishable. I have 

 found many reversed specimens in the Illi- 

 nois samples (see also S. truncata, n. sp. pi. 

 13, figs. 36-41). All other features being 

 equal, the reversal of valves is not considered 

 to be of generic or even of specific character 

 for these Kloedenellidae. The form ratio 

 of the Reynolds forms is 1.55, Kinkaid 1.51, 

 Menard, 1.55 and Golconda 1.55. 



Sansabella declivis Cooper, n. sp. 

 Plate 13, figures 4-8 



Carapace subrhomboidal, ends rounded, 

 cardinal angles prominent ; dorsum straight, 

 venter curved ; overlap pronounced around 

 free margin ; sinus deep, narrow, located 

 just in front of center; valves rise rapidly 

 from either end to produce slightly convex 

 outline as seen in dorsal view ; anterior end 

 of left valve curves sharply inward form- 

 ing narrow shelf or platform, widest on 

 antero-ventral margin, tapering to dorsum 

 and venter ; hinge typically sansabelloid ; 

 surface smooth. 



Length, 0.89 mm; height, 0.55 mm; 

 thickness, 0.40 mm. 



Golconda formation, locality 19, com- 

 mon. 



The form ratio of S. declivis is quite high, 

 about 1.6. This species may also be dis- 

 tinguished by the narrow platform on the 

 anterior end of the left valve. This feature 

 is present also on the right valve but is less 

 pronounced. 



Sansabella elongata Cooper, n. sp. 

 Plate 13, figures 1-3 



Carapace quite thick, elongate, sub- 

 rhomboidal, ends rounded ; overlap most 



