Cambrian Rocks in Cape Breton. 461 



Range. — Through the Etcheminian and Protolenus 

 Eaunas. 



Besides the species described below the following appear 

 to belong here : 



Primitia pyriformis. f ) Both of the 



P.- ■ (?) fusiformis. * /Protolenus Fauna. 



Aparchites (?) robustusf also of that fauna comes near 

 this group. 



This genus is seemingly different from Nothozoe of 

 Barrand. ISTothozoe is an oval fossil occurring in the 

 Ordovician of Bohemia, which the above author has 

 referred doubtfully to the Ostracoda. The size, however, 

 is much greater than that of the fossils we are dealing 

 with here I and no ocular tubercle has been recognized. 

 For these reasons, as well as on account of the obscurity 

 of the characters at I^othozoe, it seems inadvisable to use 

 this name for the Etcheminian species described below. 



Equal objections may be taken to the referring of the 

 Cape Breton species in question to the genus Primitia, or 

 to Aparchites, which hitherto the author has used for the 

 Lower Cambrian forms. The species of these genera are 

 small, and the, absence of an ocular tubercle in one, and 

 the presence of a median sulcus in the other, are further 

 distinctions from the species which the author has re- 

 ferred to Indiana. Few species of the genera Primitia 

 and Aparchites attain a size in which the area of the 

 valve is a tenth that of the shells referred to this genus. 

 Indiana ovalis, n. sp. PI. I, fig. 8 a to c. 



This species is ovate, broader behind than in front. 

 Hinge line about one half of the length of the valve, 

 Cardinal curve of moderate length. Anterior marginal 

 curve long, arched, posterior short, more strongly arched. 



t Roy. Soc. Can. Trans., 'vol. iv., sec. iv. ,p. 132, pi. i. figs. 3 a to c 1 and 4 a to c. 

 * N.Y. Acad. Sci., Ti-ans. vol, xiv., pp. 237, pi. vii. figs. 3 a and J. 

 t Individuals of iVoWto^oe poZZejis (Syst. Silur. Bohm, vol. i., Supp. p. 536 have an 

 area of valve 70 times greater than the largest species of Indiana. 

 34 



