PLATE XXI. 



Pago. 



BaRBATTA micronema Mook 89 



Fig. 1. Left side view of Mcok's typo of Trapezium mioron&ma. 

 Nat. Mus. Cat. Invert. FoSS., 7H1(>. 



2. Cast of a 8inall broader left valve retaining the surface markingi. 



This is like the types of Iiarbatia coalvillcnttis, and is from the same 

 locality. 



Nat. Mus. Cat. Invert. Foss., 22871. 



3. Right valve of a rather broad specimen believed to belong to tins 



species from Den Ion county, Texas. 



4. Interior view showing binge of a more elongate right valve from the 



same loci lily. 



Nat. Mus. Cat. invert. Fobs., 22870. 



Nkmodon SULCATINU8 E. & S. f 91 



Fig. 5. Cast of Left valve enlarged two diameters. 

 Nat. Mus. Cat. Invert. Foss., 22872. 



YOLDIA SUBELLIPTTCA u. sp 91 



Figs. 6,7. Opposite views of the type specimen enlarged. 

 Nat. Mus. Cat. [nvert. Foss., 22878. 



Soi.KMYAf OB8CURA n. sj) 05 



Fig. 8. Cast of left (f) valve retaining portions of the shell. 

 Nat. Mus. Cat. Invert. Foss., 22874. 

 NlJCULA OOLORADOEX6I8 U, sp 94 



Fig. 9. View of right valve enlarged. 



Nat. Mus. Cat. Invert, Foss., 22876. 



Crassatklla kxca vata n. sp 9(5 



Nat. Mus. Cat. Invert. Foss., 22875. 

 Fig. 10. Left valve of the best preserved typo. 



11. Hinge Of another left valve. 



12. Right valve slightly distorted by pressure. 



13. Hinge of same. 



234 



