26 PROCEEDINGS OF THE NATIONAL MUSEUM vol. 78 



higher. Matthew's figure is too full in the postventral region, and 

 the postcardinal angle, which should be more, as in Figure 6, is not 

 sufficiently brought out. 



In the Matthew collection eight specimens are labeled types of B. 

 spectator. Only two of these have the coarser network regarded as 

 the principal feature distinguishing the species from its nearest allies. 

 All of the other six specimens, when in condition to determine at all, 

 are the same as the types of B. perspicator and its synonym B. 

 observator s. s. 



Occurrence. — Lower Cambrian (Etcheminian, division Elc, Elc?, 

 E2^, E3e); Boundary Brook, Nova Scotia. Walcott locality, 10^. 

 (Dugald Brook). 



Cat. No. 50530 U.S.N.M. (lOp). 



BRADORIA SPECTATOR SPINOSA (Matthew) 



Plate 1, Figures 20, 21 



Bradorona spectator mut. spinosa Matthew, Canadian Rec. Sci., vol. 8, 1902. 



p. 448, pi. 1, figs. 13 a, 6; Geol. Surv. Canada, Rep. Cambrian Rocks, Cape 



Breton, 1903, p. 159, pi. 12, figs. 13 a, b. 

 Bradorona spectator mut. aequata Matthew, Canadian Rec. Sci., vol. 8, 1902, 



p. 448, pi. 1, figs. 14 o, b; Geol. Surv. Canada, Rep. Cambrian Rocks, Cape 



Breton, 1903, p. 160, pi. 12, figs. 14 a, b. 



Mutations spinosa and aequata are identical, the pecuUarities sup- 

 posed to distinguish them being greatly exaggerated in the figures and 

 disappearing after a little cleaning of the specimens. The somewhat 

 greater development of the postcardinal spine distinguishes the variety 

 from the typical form of B. spectator and the closely allied B. 

 perspicator. 



Occurrence. — Lower Cambrian (Lower Etcheminian, Ele, spinosa, 

 and E3(/, aequata) : Dugald Brook, Cape Breton. 



BRADORIA CURTA, new species 



Plate 3, Figure 10 



This interesting new species represents an extreme in the genus in 

 the length of its hinge line and the corresponding apparently greater 

 width of the valve. 



The ocular node is little developed, but otherwise the right valve 

 upon which the species is founded has all the characters of Bradoria. 

 In spite of its narrow hinge line the outline of the valve shows the 

 five unequal sides characteristic of the genus. 



Occurrence. — Lower Cambrian (Etcheminian, division E3a): Du- 

 gald Brook, Cape Breton, Nova Scotia {loc. I3l'). 



Holotype.—C&t. No. 50547, U.S.N.M. 



