372 UNIVALVE SHELLS 



Inhabits Pennsylvania. 



Greatest width less than seven-tenths of an inch. 



This species has a strong resemblance to H. ligera, 

 but in addition to its superior magnitude, its aperture 

 is proportionally wider, a character which, of course, 

 gives the whorls a greater breadth ; the whorls are 

 also fewer in number, and the distance between the 

 terminations of the lips is very perceptibly less than 

 the width of the aperture, the reverse of which ob- 

 tains in the ligera. 



$. H. *indentata. Shell depressed, pellucid, high- 

 ly polished ; whorls four, with regular, distant, ^ub- 

 equidistant, impressed lines across, of which the ire 

 about twenty-eight to the body whorl, all extending 

 to the base; suture not deeply indented ; aperture 

 rather large ; labrum simple, terminating at its infe- 

 rior extremity at the centre of the base of the shell ; 

 umbilicus none, but the umbilical region is deeply in- 

 dented. 



Greatest breadth one-fifth of an inch. 



Animal. Blued-black, immaculate. 



My Cabinet, and that of Mr. William Hyde. Se- 

 veral specimens occurred at Harrigate, the country 

 residence of my friend Mr. Jacob Gilliams, adhering 

 to stones and logs in moist places. Mr. Hyde ob- 

 tained many individuals in New Jersey. It may be 

 readily mistaken for H. arbor ea, but it is destitute of 

 the umbilicus, instead of which there is an indented 

 centre to the base, in which the labrum terminates. 

 The spire is very much depressed, and the surface 



