556 BULLETIN 53, UNITED STATES NATIONAL MUSEUM. 



21870. Ptychoceras crassum Whitfield. Plesiotypes. 



Fort Pierre (Cret.). Near Boulder, Colorado. 



Hyatt, Proc. Amer. Philos. Soc, XXXII, 1894, p. 579, pi. 14, 

 figs. 18-21. 



12279. Ptychoceras meekanum Whitfield. Cotypes. 



Fort Pierre (Cret.). Beaver Creek, Black Hills, South 

 Dakota. 



Whitfield, Rept. Geol. and Resources Black Hills Dakota, 1880, 

 p. 457, pi. 16, fig. 1. 



21092. Ptychoceras texanum Shumard. Plesiotypes. 



Navarro (Cret.). Chatfield, Navarro County, Texas. 

 Hyatt, Proc. Amer. Philos. Soc, XXXII, 1894, p. 580. 



43123. Ptychocladia agellus Ulrich and Bassler. Holotype. 



Upper Coal Measures. Near Springfield, Illinois. 



Ulrich and Bassler, Smithsonian Misc. Coll., Quart., XLV, p. 

 290, pi. 67, fig. 10, pt. 13. 



40774. Ptychocrinus parvus (Hall). Plesiotype. 



Lorraine (Ord.). Cincinnati, Ohio. 



Wachsmuth and Springer, N. A. Crinoidea Camerata, Mem. Mus. 

 Comp. Zool., XXI, 1897, p. 199, pi. 18, fig. 2. 



See Reteocrinus gracilis. 



30231. Ptychomya ragsdalei (Cragin). Plesiotype. 



Buda (Lower Cret.). Near Austin, Texas. 



Shattuck, Bull. No. 205, U. S. Geol. Surv., 1903, p. 24, pi. 12. 



15435. Ptychoparia adamsi (Billings). Plesiotype. 



Lower Cambrian. Georgia, Vermont. 



Walcott, Bull. No. 30, U. S. Geol. Surv., 1886, p. 195, pi. 26, figs, 

 i-ib; Tenth Ann. Rept. U. S. Geol. Surv., 1890, p. 649, pi. 

 96, figs. i-ib. 



24642. Ptychoparia (Euloma?) affinis Walcott. Cotype. 



Upper Cambrian. East of Hamburg Mine, Eureka Dis- 

 trict, Nevada. 



Walcott, Mon. VIII, U. S. Geol. Surv., 1884, p. 54, pi. 10, fig. 12; 

 ibid., XXXII, Pt. II, 1899, p. 457, pi. 65, fig. 8. 



24571. Ptychoparia ? annectans Walcott. Cotype. 



Lower Pogonip (Upper Cambrian). Ridge east of Ham- 

 burg Ridge, Eureka District, Nevada. 

 Walcott, Mon. VIII, U. S. Geol. Surv., 1884, p. 91, pi. 12, fig. 18. 



35234. Ptychoparia antiquata (Salter). Plesiotype. 



Flathead (Middle Cambrian). Yellowstone National Park. 

 Walcott, Mon. XXXII, Pt. II, U. S. Geol. Surv., 1899, p. 456, pi. 

 65, figs- 7, 7a. 



