210 SCALARIADiE. 



is imperforate, well rounded, and devoid of any spiral 

 carina. The aperture, which only constitutes one-fourth 

 to one-fifth of the total length of the shell, has a rounded 

 oval contour ; no external angulation is effected by the 

 junction of the outer with the pillar-lip. The peristome is 

 not otherwise thickened than by the lamina at the back of 

 the outer lip ; the shelly substance is thinly spread upon 

 the pillar-lip posteriorly, but in front it is more solid, and 

 the pillar becomes dilated and reflected at the base of the 

 shell. Our largest example is not half an inch in length, 

 and the majority of individuals do not much exceed four 

 lines and a half. 



The animal of clathratulus has been observed by Mr. 

 Clark and by Mr. Alder. In most of its features it re- 

 sembles that of Scalaria communis, but has a more slender 

 foot and shorter, more obtuse tentacula. It is entirely 

 transparent white, speckled with opaque flakes of the 

 same hue. The anterior mai'gin of the foot is deeply 

 grooved, the posterior extremity tapers to a slightly 

 rounded termination, and carries, on a simple lobe, a white 

 operculum of two very small and one very large whorls. 

 The hinder half of the sole of the foot is grooved longitu- 

 dinally and medially by a deep central depression. 



This is a southern species and rare. It occurs at Herm 

 (S. H.) ; Devon (Clark); Torbay, Fowey and Falmouth 

 (Alder); Penzance (E. F.) ; off Lundy Island (M'An- 

 drew) ; South Wales (Jeffreys and Barlee). In Ireland 

 it occurs on east and west coasts in a few places (Thomp- 

 son) ; Cork harbour and Bantry Bay (Jeffreys) ; Kilkee 

 in Clare (Humphreys) ; Arran in Gal way (Barlee). 



In the coralline crag of Sutton (Searles Wood). 



