CYLICHNA. 511 



It is tolerably strong for the size, and of an uniform 

 white both within and without. The upper or posterior 

 half of its surface, which is adorned lengthways with more 

 or less closely disposed and often curved shallow grooves, 

 whose intervals rise in elevated and subpliciform wrinkles 

 (that are never, as in a very closely allied species from 

 Aden, decussated by minute spiral lines), is flattened; the 

 lower half, which is usually more or less glossy, is smooth 

 and convex, the basal declination being well rounded. 

 More rarely the sulci, which in this case are almost obsolete, 

 seem to be continued further towards the lower extremity. 

 The crown is so broadly umbilicated as to exhibit the 

 several gyrations, the spire which consists of two or three 

 subplicated turns being sunken. The mouth is retort- 

 shaped, almost linear for the upper three-fifths of its course 

 and then more or less suddenly bulbous ; it is rounded at 

 both ends, but more particularly at the dilated one : the 

 throat is smooth. The acute outer lip, which projects 

 slightly above the crown, is straightish posteriorly, retuse 

 in the middle, where it curls inwards, and well arcuated 

 and but moderately receding anteriorly. The reflected 

 pillar lip, which is rather broad than otherwise, is furnished 

 with a slightly tubercular and subpliciform callosity. Our 

 largest example does not measure the seventh of an inch, 

 with a breadth that is decidedly not equal to the half of its 

 length.* 



* Judging from the figure, it is not improbable that the Volvaria pellucida of 

 Brown (Illust. Conch. G. B. p. 4, pi. 10, f. 45, 46) has been either constituted 

 from a worn individual of this species or of mammillata. It is thus described : — 

 " Subcylindrical, smooth, thin, pellucid, and white ; aperture whole length of the 

 body, somewhat dilating for half its extent ; outer lip rising above the body, and 

 a little thickened at its edge ; superior extremity with a subumbilicus, and a very 

 slight duplicatui-e towards the base of the columella. Length an eighth and a 

 half of an inch, breadth a little more than half its length. We found this on the 

 beach at Dunbar ; very rare." 



