6 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 9/ 



ACROTRETA LEVATA, n. sp. 



Plate I, figs. 4-6 



Another species with a very high ventral valve occurs with A. 

 dcfinita. Besides the height of the ventral valves, this species is char- 

 acterized hy its strong growth lines and the narrowness of the false 

 pedicle groove. 



Locality 55c. 



Cofypes.~\].S>.^M. no. 52108. 



WIMANELLA Walcott, 1908 



Walcott proposed IVimanella for smooth, nonplicate hrachiopods. 

 He failed to observe that his specimens of the type species were not 

 well preserved and that the ribs were effaced. Because of this error 

 many species of IVimanella have been referred to Nisusia. In fact, 

 most Middle Cambrian forms referred to Nisusia are IVitnaiiella, but 

 thus far the genus does not extend above the Middle Cambrian. 



WIMANELLA SPENCEI (Walcott) 



Plate I, figs. 27, 28 



Nisusia (Jamesella) spencei Walcott, U. S. Geol. Surv. Mon. 51, p. y2,~, text 

 fig. 62, pi. 93, figs. 7, 7a, 1912. 



LocaHties 55c, 20x, and 32X. 



Cotypes. — U.S.N.M. no. 52435 ; plesiotypes, no. 96498. 



WIMANELLA RARA (Walcott) 



Plate I, fig. 29 



Nisusia vara Walcott, (part), Smithsonian Misc. Coll., vol. 53, no. 3, p. 97, 

 pi. 9, fig. 13a, 1908; U. S. Geol. Surv. Mon. 51, p. 729, text fig. 60, 1912. 



It is possible that this single shell is not a good species but merely 

 a peculiarly preserved specimen of IV. spencei. 

 Locality 55c. 

 Holotype. — U.S.N.M. no. 52295. 



WIMANELLA NAUTES (Walcott) 



Plate I, figs. 23-26 



Nisusia (Jamesella) nautcs Walcott, U. S. Geol. Surv. Mon. 51, p. 734, pi. 93, 

 figs. 6-6b, 1912. 



Locality 55c. 



Cotypes. — U.S.N.M. no. 52432; plesiotypes, no. 96497. 



