252 



POPULAR CONCHOLOGY. 



other, but not locking into one another ; ligament in the 

 middle, thick and external ; pallial impression very deeply 

 sinuous. Animal oblong, very large and thick in proportion 

 to its shell ; mantle closed in front, widely open anteally 

 for the passage of a large linguiform foot, and posteriorly 

 for the siphons, which are deeply separated at their extre- 

 mities, united, and forming a thick mass at their bases ; 

 labial palpi triangular, narrow, lamellated on their inner 

 sides ; a large portion of the branchiae is lodged in the 

 branchial siphon.* — 6 species; also fossil. 



P. strigilatus is found in the Mediterranean ; several 

 species are British. 



Cleidophorus. Hall. — Shell equivalve, inequila- 

 teral, elliptical ; the hinge without teeth or furrow ; 

 the boss has an oblique linear pit, to which there is 

 an answering rib in the interior of the valve; the 

 upper surface is concentrically striped: as the muscular 

 and pallial impressions are unknown, the exact situation 

 in the systematic arrangement must remain doubtful ; the 

 description of the hinge resembles in some measure that 

 of Solenomya. — Fossil. 



Family 7. — PHOLADEA. 



The animals of this family have the mantle almost 

 entirely closed, a thick short foot, the siphons united 

 together, the gills very long and pointed, free at the 

 ends, and reaching far into the breathing tube. The 

 shell has no true hinge, and no ligament ; under the 

 bosses is a spoon- shaped process, to which the strong foot 

 muscles are attached. The animals bore into stone, wood, 



* Forbes s British Moll. 



