340 NATICID^. 



above, is rather quick ; the last two or three are abruptly 

 elevated ; the apex is very blunt, and the earlier coils 

 depressed ; the penult volution is rather high. 



The shape of the mouth, which fills rather less than two- 

 thirds of the ventral length, is oblong- elliptic; it is narrow, 

 yet in the middle is broader than, or quite as broad as, 

 that portion of the body which is in a line with it ; its 

 basal recession is very trifling. 



The lateral projection of the thin and simple outer lip is 

 not considerable, and its arch does not at all appi'oach a 

 semicircle in extent. A thin layer of white enamel com- 

 pletes the peristome, but is not diffused over the body as 

 in certain Natic<£. The outline of the inner lip is a little 

 sinuated, for the body sometimes swells out a little above, 

 and the free edge of the pillar is frequently a little incurved. 

 The pillar lip is at first pressed close to the body, and 

 though straightish in the young, becomes arcuated and 

 dilated in mature specimens at its anterior junction with 

 the right lip, where the slightly patulous base of the aper- 

 ture is contracted to a more or less distinct angle. There 

 is no axial perforation, but a minute crevice in the fry 

 marks the ordinary position of an umbilicus. The oper- 

 culum has a dirty yellow cast. 



One of our foreign examples (from Newfoundland) is an 

 inch and a quarter long, and eleven lines in breadth, but 

 none of the British examples we have yet seen approach 

 these dimensions : the one originally described by Dr. 

 Johnston measured three-fifths of an inch long and was 

 scarcely two-fifths of an inch in breadth. 



This curious and rare shell, with the animal of which we 

 are as yet unacquainted, was discovered by Dr, Johnston 

 on the coasts of Berwickshire. Mr, Howse has taken it at 

 Sunderland, and Mr. Bean informs us that one very fine 



