OF CONCHOLOGY. 17 



tUf we value ; and because we consi- 

 der it more properly the summit of 

 the shell, than the opposite extremity. 



JBase, is the reverse of the above, 

 or that part of the shell immediately 

 Opposite the summit. Plate 1st, figrs. 

 6th and 7th, dd. 



SideSi the right and left parts of the 

 valves ; plate 1st, ^g. 6th, c. 



Anterior slope, is that part of the 

 shell in which the ligament is situated. 

 In viewing the anterior slope in front, 

 the beaks of the shell retire from view. 

 Plate 1st, ^g. 4th, ^. 



Posterior slope, that part of the 

 ishell opposite the anterior slope ; in 

 viewing it in front, the beaks point to 

 you. Plate 1st, fig. 4th, k. 



Disk, the convex centre of a valve, 

 or most prominent part of the valve, 

 suppose it with its inside lying under- 

 most. Plate 1st, fig. 4th, a. 



Inside, the concave part of a valve. 

 Plate 4th, Gg, Cth, n. 



