DESCRIPTION. 131 



nal margin crenate, internal one entire ; area with 

 angular brown lines and impressed marks. 



Inhabits the Mediterranean,. Red, Atlantic, and 

 Indian Seas. 



Fig. 6, A. granosa. 

 Shell subcordate with muricated ribs. 

 Lister Conch. Tab. 241. Fig. 78. 

 Specimen white, nearly equilateral ; ribs 20, 

 tuberculate with obtuse spines. 



Inhabits the Indian and American Ocean. 



Fig. 7. A. Glycymeris. 



Shell suborbicular, gibbous, substriate. 



Lister Conch. Tab. 247. Fig. 82. 



Specimen white, marked with irregular, inter- 

 rupted, transverse bands, and angular lines of red- 

 dish brown, white within; the longitudinal and 

 transverse striae extremely fine ; hinge bowed. 



Inhabits the English and other seas. 



PLATE IX. 

 Fig. 1. OsTREA Radida. 

 Shell sub-eqviivalve, with 12 convex rays, and 

 decussate, crenate striae. 



