ART. 4 CAMBRIAN CONCHOSTRACA — ULRICH AND BABBLER 21 



Occurrence. — Lower Cambrian (Etcheminian, E26, E36): Dugald 

 Brook, Cape Breton. (Walcott locality lOg., I'^n" .) 

 Holotype.—C&t. No. 50541, U.S.N. M. (lOg.) 



BRADORIA OVAUS (Matthew) 



Plate 1, Figure 18; Plate 3, Figure 6 



Indiana ovalis Matthew, Canadian Record Sci., vol. 8, 1902, p. 461, pi. 2, 

 figs. 8a-8c. 



Indiana ovalis and mutation prima Matthew, Geol. Surv. Canada, Rept. Cam- 

 brian Rocks Cape Breton, 1903, p. 170, pi. 13, figs. 8a-8c. 



This fine species is represented by a single specimen in the set of 

 Matthew's types before us.^ Another much better preserved example 

 is in the Walcott collection from Dugald Brook, the type locality. 

 The shell of Matthew's type is mostly exfoliated and its outline some- 

 what obscured and injured in cleaning, but after a very careful com- 

 parison of the two specimens, we have not the least doubt of their 

 specific identity. Judging more especially from the Walcott specimen, 

 the species approximates B. robusta and B. rugulosa in surface orna- 

 ment, and the former also somewhat in general form. It is, however, 

 proportionately longer, has a narrower anterior end and rather more 

 uniformly rounded posterior margin. In shape B. ovalis is not greatly 

 different from B. scrutator, B. benepuncta, and B. obesa, but it is dis- 

 tinguished from the first two by its rounded posterior, from the latter 

 by its more elongate form and narrower anterior, and from all three 

 by the concentric arrangement and somewhat rugulose character of 

 its surface markings. 



The ocular node is well developed; hence the species has no very 

 close relations to the species to which Matthew's genus Indiana is 

 restricted. 



Occurrence. — Lower Cambrian (Etcheminian, Ele, E26, E3e): 

 Dugald Brook, Cape Breton, Nova Scotia. Mutation prima, Cold- 

 brookian, Dugald Brook. 



Plesiotype.—C&t. No. 81378, U.S.N.M. {lOp). 



BRADORIA RUGULOSA Matthew, emended 



Plate 1, Figure 17 



Bradoria rugulosa Matthew, Bull. Nat. Hist. Soc. New Brunswick, No. 18, 

 1899, p. 205, pi. 3, figs. 3o-3d; Canadian Record Sci., vol. 8, 1902, p. 456, 

 pi. 11, figs. Sa-Sd; Geol. Surv. Canada, Rept. Cambrian Rocks Cape Breton, 

 1903, p. 166, pi. 13, figs. Za-Zd. 



Bradorona observator mut. laevis Matthew, Canadian Record Sci., vol. 8, 1902, 

 p. 450; Geol. Surv. Canada, Rept. Cambrian Rocks Cape Breton, 1903, 

 p. 161. 



The three specimens upon which the so-called "mutation" laevis 

 is founded are of the same form, but this form is not clearly related 



• There are two specimens so labeled, but the second is undoubtedly distinct from the figured type, hav- 

 ing coarser surface punctae and a general aspect suggesting identity with B. scrutator or B. vigilans. 



