248 C O N C H O L O G Y. 



The lecond family is theSpondyli. The 

 Spondyles are mod generally eared Shells 

 with unequal valves, rude or uncouth in 

 fhape, partaking of the ruggednefs of the 

 Oyfter with fomewhat of the Efcallop 

 form, fo as to feem a medium between the 

 two families. However, the Spondyles 

 like the Efcallops, have fome fpecies with 

 equal valves, and Vv^ithout ears. 



The head characler is the hinge, which 

 in the upper Shell confifh of a triangu- 

 lar hollow and cartilage, like the Efcal- 

 lop, in the very center, on each fide of 

 which is a large deep cavity, and a very 

 large thick and prominent tooth or joitit 

 lies on each fide of the cavity. PI. VL 



fig. 4. ^a 



The fummit and beak of the under valve 



is alfo extremely thick and ftrong, and ex^ 



tends from the hinge outwards into a broad 



triangular flope or flat. 



Some 



