Anomalodonta gigantea. 



17 



Anomalodonta gigantea. — (S. A. Miller.) 



Shell equivalve, inequilateral, alate posteriorly and compressed, more 

 convex toward the urabones and anterior side, anterior side abruptly 

 declining, beaks rather sharp and sliglitly incurved. Surface marked 

 by 30 to 40 strong radii, same width as intermediate spaces, which are 

 concave grooves marked with concentric stride, giving much the same 



Fig. 7. A. gigantea. Left valve showing hinge line and muscular impression. 



external appearance as those of an Ambonyckia radiata. Shell marked 

 exteriorly, toward the margin, with lines of growth and concentric 

 stripe, which cross the radii, rendering it likely that concentric strire 



Fig. 8. A. gigantea. Eight valve, hinge line. 



crossed the radii over the whole surface of the shell, though they ap- 

 pear now to be smooth. Byssal sinus immediately below the beak 



