102 



other times only two very obscure ribs, and often no in- 

 dication of either : the young state of the spinous variety 

 has been referred to the Genus Solen, and it is very re- 

 markable that Lamarck should not have discovered its 

 relation to Saxicava rugosa. 



The specimens before us arefrom the Suffolk Crag, they 

 were collected by the Rev. G. R. Leaths, and have all 

 the visible characters of genuine Crag Fossils, but they 

 agree in form with the recent species, and Mrs. Cobbold 

 has sent us a small specimen which she found amongst 

 others in holes in Septaria, immediately below the Crag 

 at Holy wells, which would lead us to suspect them to be 

 of comparatively modern extraction. The middle figures 

 have some remains of the spines belonging to the variety. 



