208 



SAXICAVA. 



Platyodon cancellatus, Conr., Pla-ty'-o-don can-sel- 

 la'-tus, Fig. 177. Closely resembling the last is the 

 species named above. The genus takes its name 

 from its broad hinge-tooth, which is not equal, how- 

 ever, to that of the Mya. The valves are thicker 

 than those of that species, greatly bulged, and gap- 

 ing posteriorly. Concentric markings are very plain, 

 but radial lines are faint. Color white; length two 

 or three inches. I found them abundant on the 

 shore of Bolinas bay; they are found also to the 

 southward. 



Fig. 17S. 



The shell of the little Saxicava artica, Linn., Sax- 



l-ca -va arc 

 ular. The 



-ti-ca, is small, 

 beaks 



are near 



thin, 

 the 



which is abruptly terminated. 



wrinkled and irreg- 

 front of the shell, 

 Ligament small, 



