176 CONCHYLIA— D/THYE^. 40. 



Shell oval-triangular or oblong, equivalve, inequilateral, closed .- 

 with the beaks close together. Hinge with an oblique projecting 

 spoon-shaped tooth in each valve : lateral teeth on each side nu- 

 merous, sharp-pointed, inclining outwards, and alternately closing 

 together. Ligament internal. 



Except in its numerous teeth, this genus has nothing in common 

 with the Area and the Pectunculus. The primary tooth consists of 

 an oblique hollow projecting inwards horizontally, in which the liga- 

 ment is fixed : and the lateral ones of slender sharp teeth, like the 

 pectinations of a comb, the middle ones longer. 



* Margine interno crenulato. 1. 

 The inner margin finely notched. 



Nucleus: NucuLA testa oblique ovatd subtrigond, loeviusculd nitidd. 



Shell obliquely heart-shaped and somewhat triangular, glossy and 

 nearly smooth. 



Tab nost. 13. fig. 4. 

 Area Nucleus, Linn. Syst. Nat. p. 1143. 

 Gmelin, Syst. p. 3314. 

 Turton, Linn. Syst. iv. p. 257. 

 Pennant, Brit. Zool. iv. p. 217. 

 Donovan, British Shells, ii. tab. 63. 

 Montagu, Test. Brit. p. 141. 

 Linn. Trans, viii. p. 95. 

 Turton, British Fauna, p. 161. 

 Dorset Catal. p. 37, tab. 12. fig. 6, 



