Cambrian Rocks in Cape Breton. 451 



E. 1. &, carapace, length 4mm; width 3 mm; depth 2|mm. 



a 31 « u 3 u u i^ u 



E. 2. c. right valve " 4^ " " 3| " " 1 



Mutation LIGATA, n. miit. PL I., fig. 17. 



Oval, cardinal curves long, anterior marginal curve 

 straight, posterior ornamented with a row of small tuber- 

 cles ; a similar row extends direct from the lower end of 

 the posterior cardinal curve toward the lower end of the 

 valve, near which it curves forward. Ocular tubercle 

 obscure, it appears to be represented by four small tuber- 

 cles ; but the furrow is well marked. 



Sculpture. Punctation rather coarse; anastomosing ridges 

 near the two ends of the valve, parallel to the margin. 

 Size. Length 4 mm ; width 3 mm ; depth of two valves 2 

 mm. 



Horizon and localitij . Assise E. 3. e.. Upper Etcheminian, 

 at Dugald Brook. Pare. 



" BRADORIA." 



" In the Protolenus Fauna are two species of Ostracoda 

 which for want of other known relationship were referred 

 to the genus Primitia. It would appear now that they 

 are representatives of an ancient type of crustaceans which 

 has species in the Etcheminian Fauna. Though having 

 the general form of Primitia, Primitiella and Aparchites 

 they do not have the median pit, or sulcus of the first, 

 the shallow median depression of the second, or the smooth 

 valve of the third. Their most marked character is a 

 prominence or tubercle just at the front of the hinge-line; 

 from the smoothness of the summit of this tubercle, and 

 its advantageous position for vision, it is supposed to be 

 an ocular tubercle. Some of the species have close 

 behind this tubercle, a short vertical furrow ; or the fur- 



* Nat, Hist. Soc. N. Brunswick, Bull. vol. iv, p. 204. 



Named for the Bras d'or, a salt water lake occupying- the interior of the island of 

 Cape Breton. 



