AET. 17 MOLLUSKS FROM WYOMING REESIDE AND WEYMOUTH 9 



at an angle of about 70° from the beak. Sculpture of fine concentric 

 lines with a few low obscure folds parallel to them. Internal char- 

 acters entirely unknown. Length, 23 millimeters; height, 14 milli- 

 meters; depth of valve, as preserved, about 2.5 millimeters. 



No species in the American cretaceous deposits, known to the 

 writers, seems near enough to Tancredia? Uncolnia7ia to require 

 comparison. 



Holotype.— Cat. No. 73767, U.S.N.M. 



Family VENERIDAE Leach 



Genus APHRODINA Conrad 



APHRODINA? ASPENANA, new species 



Plate 1, Figures 7, 8 



A mold of the exterior of a right valve retaining the central part 

 <5f the shell and therefore showing some internal characters and a 

 second, incomplete mold of the exterior represent this species. The 

 outline of the valve is round-oval with all the margins evenly con- 

 vex; valve rather shallow for the genus; angle at the beak about 

 120°. Sculpture of unequal concentric lines. Pallial line shows deep 

 but blunt sinus; muscle scars not prominent. Hinge and other 

 characters unknown. 



Length, 27 millimeters; height, 23 millimeters; depth as preserved, 

 5 millimeters. 



Of the seemingly related forms of comparable age, " Callista " 

 orbicvlata (Hall and Meek)^" is higher and stouter; " Callista^'' tenuis 

 (Hall and Meek)^^ is smaller and stouter. The much later species 

 " Callista " deweyi Meek and Hayden ^^ has some resemblance, but 

 the outline of the valve is less orbicular. 



Holotype and paratype.—Cai. No. 73768, U.S.N.M. 



Family TELLINIDAE Deshayes 

 Genus LINEARIA Conrad 



LINE ARIA? Bpecieg 



Plate 1, Figure 9 



A single natural cast of the exterior of a valve suggests Linearia 

 in its general appearance, but so few details are available that no 

 further assignment is warranted. The specimen is depressed, sym- 



^0 Meek, F. B., Invertebrate Cretaceous aud Tertiary fossils of tlie upper Missouri coun- 

 try : U. S. Geol. Survey Terr. Kept., vol. 9, p. 186, pi. 5, fig. 2, 1876. 

 " Idem, pi. 5, fig. 1. 

 " Iden?', p. 182, pi. 17, flg. 15. 



23909—31- 



