224 PYRAMIDELLID^E. 



Pyramis nitidisnimus. Brown, lUust. Conch. G. B. p. 15. 



Chcmnitzia nitidissima. Alder, Cat. Moll. Northumb. and Durh. p. 49. 



Although smooth to the naked eye, and represented as 

 such by the earher writers, the surface of this shell, when 

 not abraded, displays beneath the microscope an exquisitely 

 delicate spiral liueation. 



This graceful little species is very slenderly subulate, 

 almost indeed aciculate, extremely thin, and of an uniform 

 glossy and transparent snow white. Besides the hetero- 

 strophe apical coil, which is narrow and prominent, there 

 are eight volutions, which are most minutely and densely 

 striated throughout in a spiral direction, are of slow longi- 

 tudinal increase, and more or less high, the proportion of 

 length to breadth in the penult turn being sometimes as 

 three to four, sometimes as five to eight. They are mode- 

 rately, but decidedly, ventricose, and almost equally round- 

 ed above and below : the suture that divides them is 

 profound and slanting, or at least moderately oblique. 

 Tbe body, whose axis is imperforated, is rounded at the 

 base, but its declination is rather quick. The mouth, 

 which occupies a fifth of the entire length, is simply oval, 

 and is not distinguished by any sculpture. The outer lip 

 is acute, simple, and not expanded ; the receding pillar-lip 

 is curved, narrow, and not distinctly reflected. Two lines 

 is the full length of individuals whose basal breadth is but 

 the fifth of that measurement. 



The animal has not yet been observed, nearly all the 

 examples of this rare species having been procured from 

 shelly sand. Dr. Johnston has taken it at Cheswick 

 (Alder), which is almost the only recorded northern loca- 

 lity. Padstow (Rev. W. Moles worth from Dr. Good- 

 all) ; Falmouth, and Cork Harbour (Jcftreys) ; Exmouth 



