24 PROCEEDINGS OF THE NATIONAL MUSEUM vol.78 



In the Etcheininian the species occur in divisions El6-El(f, E2a, 

 E2b, ESd-ESf. Walcott locahties lOp, 10p\ IZd, ISd', 13n', 13n", 

 13t, ISf, lOp. 



Plesiotypes.—CeLt. Nos. 50517 (13^), 50518 (13(f), U.S.N. M. 



BRADORIA ROBUSTA LONGULA, new variety 



Plate 2, Figure 5 



A specimen in the Walcott collection from Dugald Brook indicates 

 a species that, while readily distinguishable, is j^et manifestly closely 

 aUied to B. robusta. The principal difference is the greater length of 

 its cardinal margin; but as this pecuharity imparts a strikingly 

 different outline to the valves, it is thought to be of importance. 

 Unfortunately we have seen but a single specimen, and therefore 

 can not say how constant these peculiarities may be. The surface 

 markings are of the concentric pattern found in B. robusta and B. 

 rugulosa. 



Occurrence. — Lower Cambrian (Lower Etcheminian, div. El6): 

 Dugald Brook, Cape Breton, Nova Scotia (locality 130- 



Holotype— Cat. No. 81379, U.S.N.M. 



BRADORIA TONTOENSIS, new species 



Plate 3, Figure 20 



Of this species but a single specimen, a right valve, has been 

 discovered. It is, however, very readily distinguished from all the 

 other species of the group so far knowna by its outline and particularly 

 by the obsolescence of the ocular node. This latter feature casts 

 some doubt upon the generic reference; but as all the other features 

 of the valve seem to be in harmony with the genus, the species may 

 provisionally at least be fittingly placed here. Compared \yiih other 

 species of Bradoria we note considerable resemblance to such forms as 

 B. robusta and B. ovalis. From both, however, it is at once dis- 

 tinguished bj^ its more sharply defined cardinal angle and by the rela- 

 tively greater height. From B. robusta it is further distinguished by 

 the more nearly vertical anterior edge and the greater fullness of the 

 posterior ventral part of the outline. 



Occurrence. — Middle Cambrian (Bright .Ajigel shale): Near mouth 

 of Bass Canyon, Grand Canyon of the Colorado, Ariz. 



Holotype.— Cat. No. 81377, U.S.N.M. 



BRADORIA PERSPICATOR (Matthew) s. s. 



Plate 1, Figures 6-9; Plate 3, Figure 12 



Bradorona perspicator Matthew, Canadian Record Sci., vol. 8, 1902, p. 444, 

 pi. 1, figs. 8a-8d; Geol. Surv. Canada, Rept. Cambrian Rocks Cape Breton, 

 1903, p. 1.56, pi. 12, figs. 8a-8d. 



