12 University of Texas Bulletin. 



PERNIDAE. 



Genus INOCERAMOUS Sowerby. 



INOCERAMOUS sp. 



PL I, fig. 5. 



Dimensions. Length, 50mm. ; breadth, 35mm. 



Description. Shell subovate, ventricose, inequilateral; hinge 

 oblique to long axis; umbo narrow, prominent, incurved. Shell 

 ornamented externally and internally with rounded, concentric 

 plications, separated by grooves of similar width. The plica- 

 tions are very fine at the beak, but gradually increase in size 

 toward the base. 



There is only one specimen of this species in this collection, 

 and it is too fragmentary for determination. The outlines shown 

 in the figure may not be accurate, but are the result of following- 

 down the parts of shell and cast while removing the rock cover- 

 ing them. 



Locality. Barton Creek, Austin, Texas. 



OSTREIDAE. 



Genus ALECTRYOXIA Fischer. 



ALECTRONIA CARINATA Lamarck. 



PL I, figs. 1, 2. 



Ostrea carinata Roemer, 1849, Texas, p. 394. 



Ostrea carinata Roemer, 1852, Die Kreide. von Texas, p. 75, 



Taf. 9, fig. 5. 

 Ostrea carinata Conrad, 1857, Rept. U. S. and Mex. Bound. 



Surv., Vol. I, Pt. 2, p. 156, PL 10, fig. 6. 

 Ostrea carinata White, 1884, Fourth Ann. Rept. U. S. Geol. 



Surv., p. 293, PL 43, figs. 1-4. 



Ostrea carinata Hill, 1889, Texas Geol. Surv., Bull. No. 4, p. 6. 

 Alectryonia carinata Hill, 1898, U. S. Geol. Surv., Bull. No. 151, 



p. 26. 



Dimensions. Length, 42mm. ; breadth, 10mm. 

 Description. Shell narrow, curved, moderately auriculate ; 

 beaks depressed, slightly twisted; surface ornamented with 

 twelve or more strong, narrow, sharp ribs, which, in some speci- 



