50 LITTORINIDyE. 



swollen and elevated in the middle, convexly shelving 

 above, and abruptly but still convexly declining to a 

 rounded termination anteriorly. From the suddenness 

 of the basal slope, and the recedence of the outer lip in 

 front, the shell appears, when viewed from above, to lean 

 considerably forward. The mouth is ample, being equal 

 in size to the rest of the ventral area, and occupying about 

 five-sixths of the total length ; it is rather obliquely pro- 

 minent, especially anteriorly, is longer than broad, and 

 of an oval-suborbicular contour. The outer lip is very 

 thin, well arcuated both above and below, and recedes con- 

 siderably at the base of the shell. The pillar, which is 

 shining, flattish, or even a little hollowed, and of a paler 

 or darker liver- colour, is concave at the free or outer 

 edge, and arcuated at the other margin ; hence it is apt 

 at times to bear a narrow crescent-like form ; it mani- 

 festly shelves inward, and is more or less broad, yet less 

 so at its confluence with the outer lip, than it is higher 

 up. There is often a little indentation at the ordinary 

 site of the umbilicus in other genera. Our largest ex- 

 ample only measures the fifth of an inch across, and is 

 a trifle less in length. 



The confusion attending the history of this minute 

 Littorina, prevents our indicating its distribution with 

 accuracv, and saying more than that it was first dis- 

 covered at Scarborough, by that indefatigable and ob- 

 servant Conchologist, Mr. William Bean, to whose re- 

 searches in this branch of Natural History we owe our 

 warmest thanks. Mr. Jeftreys possesses specimens ga- 

 thered on the Northumberland coast by INIr. King. He 

 considers it a variety of littoralis. 



