62 BULLETIN 53, UNITED STATES NATIONAL MUSEUM. 



191. Arcopagella (?) macrodonta Meek. Holotype. 



Dakota (Cret.). Big Sioux River, three miles above its 

 mouth, South Dakota. 



Meek, Rept. LT. S. Geol. Surv. Terr., IX, 1876, p. 202, pi. 1, fig. 2. 



12411. Arcopagella mactroides Meek. Holotype and paratype. 



Mentor (Cret.). Twelve miles southwest of Salina, 

 Kansas. 



Meek, Fourth Ann. Rept. U. S. Geol. Surv. Terr., 1871, p. 309, 

 text figs. A, B; Rept. U. S. Geol. Surv. Terr., IX, 1876, p. 

 202, pi. 2, figs. 4a, 4b. 



13328. Arcopagia unda Conrad. Holotype. 



Miocene. Shore of Santa Barbara Count}', California. 



Conrad, Rept. Expl. and Surv. R. R. Miss. Riv. to Pacific Ocean, 

 VII, 1857, p. 192, pi. 4, figs. 3, 4. 



[May be the same as Metis alta (Conrad). W. H. Dall.] 



24560. Arethusina americana Walcott. Cotype. 



Upper Cambrian. North of Dunderberg mine, Eureka 

 District, Nevada. 

 Walcott, Mon. VIII, U. S. Geol. Surv., 1SS4, p. 62, pi. 9, fig. 27. 



42436. Arges wesenbergensis paulianus Clarke. Cotype. 



Trenton (Orel.). St. Paul, Minnesota. 



Clarke, Geol. and Nat. Hist. Surv. Minn., Final Rept., Ill, Pt. II, 

 1894, p. 745, fig. 64. 



109294. Argyrotheca schucherti Dall. Holotype. 



Miocene. Jackson Bluff, Ocklockonee River, Florida. 



Dall, Trans. Wagner Free Inst. Sci. Phila., Ill, Pt. VI, 1903, 

 P- 1539. pl. 58, fig. 8. 



35230. Arionellus levis Walcott. Holotype. 



Middle Cambrian. Crowfoot section, Gallatin Range, 

 Yellowstone National Park. 



Walcott, Mon. XXXII, Pt. II, U. S. Geol. Surv., 1899, p. 462, 

 pl. 65, fig. I. 



1 180. Arionellus | Crepicephalus ) oweni Meek and Hayden. 



Holotype. 

 Upper Cambrian. Near head of Powder River, Big Horn 

 Mountains, Wyoming. 



Meek and Havden, Proc. Acad. Nat. Sci. Phila., for 1861, p. 436; 

 Arner. Journ. Sci. (2), XXXIII, 1862, p. 74, fig. 4. 



= Ptychoparia oweni. 

 See Agraulos oweni. 



46092. Aristerella nitidula Ulrich. Cotypes. 



46093. Black River (Ord.). Chatfield and St. Paul, Minnesota. 



Ulrich, Geol. and Nat. Hist. Surv. Minn., Final Rept., Ill, Pt. II, 

 1894, p. 524, pl. 35, figs. 30-39. 



