234 NEW YORK STATE MUSEUM 



Macrodus matthewi nov. 



Shell quite small, obliquely ovate, much broader behind with 

 obliquely curving lower margin and broadly rounded posterior 

 extremity. The hinge is not long and slopes at its posterior end 

 to the posterior curve. The beak is well forward, nearly terminal, 



Macrodus matthewi 



umbones prominent, umbonal ridge arched, oblique, high, fading 

 out posteriorly. A broad sinus lies medially in front of the 

 umbonal ridge and produces an inward curve on the lower shell 

 margin. Length and posterior hight of the shell nearly the same. 

 Lower Devonic. Dalhousie, N. B. 



Macrodus ? baileyi nov. 



Shell small, elongate, gradually expanding backward. Beaks 

 at about one third the length of the hinge from the anterior 

 extremity. Hinge line rounding broadly backward. Umbonal 

 ridge or crescence line high, posterior, well defined in early growth 



Macrodus ? baileyi 



but becoming obscure in later stages. Anterior extremity well 

 rounded, the lower margin of the valves incurving medially and 

 rounding again to the broader and rather blunt posterior extremity. 

 The surface of the valves is rendered concave medially by a broad 

 not sharply defined sinus passing from the umbones to the lower 

 margins. Contour quite regularly convex on each side of the sinus. 



