S60 MARINE SHELLS 



it has been either figured or described distinctly in 

 any work to which I can refer. The inner margin, 

 particularly between the ribs, is sometimes of a dirty 

 reddish-brown colour. I have not seen this speciei 

 on the southern coast. 



The variety occurs on the coast of New England, 

 and several specimens are preserved in Mr. William 

 Hyde's cabinet. One specimen is of a fine bright 

 orange-colour, and on one of the valves only, are the 

 concentric bands of blackish : the margins, which de- 

 cline from the beaks, are transversely mottled with 

 white. Another has one valve blackish-brown, with 

 about a dozen rather large white spots on the disk, 

 longitudinally disposed, and white transverse varie- 

 gations on the umbones and beaks ; the margins, 

 which decline from the beaks in both valves, are 

 similarly coloured, and varied with transverse white 

 marks ; the opposite valve is yellowish-white, with 

 the usual bands. It must, however, be observed, that 

 the epidermis of both these specimens was removed 

 by muriatic acid. It is probable that the examina- 

 tion of numerous specimens, will prove this to be a 

 distinct species, if so, it may be distinguished by the 

 name of P. borealis. 



2. P. *dislocatus. Shell suborbicular, with twen- 

 ty or twenty-two elevated rounded ribs, and very 

 numerous concentric wrinkles ; longitudinal striaa 

 none; whitish tinged with yellow or reddish, with a 

 few narrow, transverse, interrupted, and dislocated, 

 sanguineous, undulated lines, and five or six pale- 



