62 CONCHYLIA— Z)/r^F/2J. 21. 



Shell flat, nearly orbicular, equivalve, inequilateral, a little open 

 at the sides. Hinge of one valve with a single tooth and trans- 

 verse linear lateral one each side ; of the other valve with a 

 cavity in the middle and a transverse deeply cloven lateral 

 tooth each side, the segments of which divaricate from the 

 beak. Ligament internal. 



Montagu had seen only one valve of this extremely rare and 

 valuable shell, and was consequently unacquainted with the whole 

 of the internal structure. 



In one of the valves is a central erect primary tooth between 

 two hollows ; and on both sides from the hinge runs a nearly 

 straight transverse rib a little within the margin, upon each of 

 which is placed a small tooth-like prominence not very remote 

 from the hinge ; the rib also on one of the sides is furnished with 

 a small internal oblique cavity, not unlike the spoon-shaped 

 tooth of the Anatina convexa. 



In the other valve there is no primary tooth, but a large 

 triangular cavity for the reception of the tooth of the opposite 

 valve: and the lateral teeth are transverse and divided from their 

 origin, forming acute angles, the points of whicii are close to 

 the cardinal cavity, with the inner limb continued by a rib like 

 that in the opposite valve. 



■jiiiiiiiiKisum. Lepton testd sqiiamoso-punctatd. 



Shell punctured in a scale like manner. 



Tab. nasi. 6, fig. 1 to 3. 

 Solen squamosus. Montagu, Test. Brit. p. 565. 

 liinn. Trans, viii. p. 48. 



