22 SMITHSONIAN MISCELLANEOUS COLLECTIONS VOL. 98 



collected. The Spence shale form previously identified as A. sulcata 

 has been described as A. levata Resser. 



The plesiotypes add to our knowledge of the species by presenting 

 illustrations of specimens showing the exterior features. 



Near Paris, Bear River Range, and localities 54s, 19s. 



Holotype. — U.S.N.M. No. 35275 ; plesiotypes. No. 52109. 



ACROTRETA EUCHARIS, n. sp. 



Plate i, figs. 15-18 



Acrotrefa pyxidicnla Walcott (part) (not White), U. S. Geol. Surv. Mon. 51, 

 p. 701, pi. 69, figs. 3-31, 1912. 



This is the commonest species of Acrotrcta in this formation, being 

 represented by many specimens both in the Wasatch Mountains and 

 on the eastern slopes of Bear River Range. It is a small brachiopod, 

 and since it does not exceed 2 mm. in diameter Walcott confused it 

 with A. pyxidicnla White, an Upper Cambrian species from the 

 Schellbourne Range, Nevada. As a matter of fact, Walcott's descrip- 

 tion of A. pyxidicnla is based on the Idaho specimens. 



The photographs fail to bring out the height of these minute shells, 

 which, however, is shown in Walcott's drawings. It will be observed 

 that this species differs from A. sulcata because the median groove 

 is very much shorter and the median septum of the dorsal valve also 

 is shorter. In A. cucharis the apex is much closer to the posterior 

 margin than in A. sulcata. 



Localities 54s, 322, and 59f . 



Coty pes— U.S.N.M. Nos. 52147, 52150. 



ACROTHYRA Matthew, 1901 



ACROTHYRA MINOR Walcott 



Plate 1, figs. 26-29 



Acrothyra minor Walcott, Proc. U. S. Nat. Mus., vol. 28, p. 303, 1905; 

 U. S. Geol. Surv. Mon. 51, p. 717, text fig. 59, pi. 76, figs. 4-4D, 1912. 



Locality 54s. 



Holotype and paratypes. — U.S.N.M. Xos. 52050, 52051. 



OBOLIDAE King 

 LINGULELLA SALTER, 1866 

 LINGULELLA EUCHARIS Resser 

 Plate 1, figs. 30-32 

 Lingnlella cucharis Resser, Smithsonian Misc. Coll., vol. 97, No. 12, p. 5, pi. 1, 

 figs. 1-3, 1939- 

 Walcott identified the specimens of this species with L. desiderata, 

 L. helena, and L. isse but figured none of them. 





