464 Canadian Record of Science. 



SCHMIDTELLA (?) PERTETUS, PI. II, figS. 11a tO C. 



Schmidtella ? pervetus, n. sp. Kat. Hist. Soc. X.B. Bull, vol iv., p. 206, pi. iv., flgs. 

 3 a to c. 



"Only the right (?) valve is known, [others found since.] 

 The valve is moderately arched and without furrows, and 

 its greatest fullness is in the upper half. The hinge- 

 margin, w^hich is more than half of the length of the 

 valve, is straight and is formed by an infolding of the 

 edge, which is wuthout a furrow. ISTo marginal fold was 

 observed. 



Sculpture. — The surface is covered with minute pits, 

 closely placed ; the raised spaces between the pits become 

 so prominent on the lower part of the valve that the 

 surface seems tuberculated, rather than pitted ; toward the 

 lateral and the lower edges these tubercles are arranged in 

 rows, so that there the valve seems covered with obscure 

 ridges parallel to the margin. At the opposite side of the 

 valve, towards the hinge-line, the pits become very fine, 

 and the surface of the valve has a shining appearance. 



Size.- — Length, 3 mm. ; width, 2\ mm." ; depth, 1 mm. 



Horizon and Locality. — In Assise E. 3 e. of the Upper 

 Etcheminian, Dugald Brook. 



Some examples from the original bed show a valve 

 highest in the middle, and with a hinge-line half of the 

 length of the valve. There are traces of a narrow margi- 

 nal fold. 



'•This species differs" from Bradoria rugulosa in its coarser 

 ornamentation and in the broader curve of the lower mar- 

 gin. "Erom S. cambrica of the Protolenus Eauna it differs 

 in the less protuberant centre of the valve and the nar- 

 rower and straighter infolded border at the hinge-line. 

 The marginal fold is also more distinct in S. cambrica, 

 which does not have the concentric marginal ridges of this 

 species." 



Mutation concixxa, d. niut. 



Highest part of the valve about two-fifths from the 



