281 SCISSURELLID.E. 



placed underneath : foot oblong, rather elongated, rounded at 

 each end, and somewhat broader in front, furnished mth two 

 pointed lappets on either side of the anterior part : appe^idages 

 or pedal filaments two on each side behind the lappets, one in 

 the middle, and the other close to the tail ; these are long, 

 slender, and serrated or cirrous. 



Shell somewhat globular, w4th a slope towards the middle 

 or periphery, of a delicate texture, semitransparent, and 

 glossy : sculpture, numerous extremely fine and curved longi- 

 tudinal ribs, which are interrupted in the middle or circum- 

 ference of each whorl by the encircling slit and canal ; they are 

 more close -set on the under than on the upper surface of the last 

 whorl, and are to a greater or less extent decussated in the 

 interstices by minute spiral striae: colour pearl-white: epi- 

 dermis thin and caducous, pale yellowish-brown : spire usually 

 rather depressed, but variable in that respect : whorls 4, 

 flattened above, and rapidly enlarging ; the last ls three 

 or four times the size of all the others put together : slit long 

 and narrow, nearly central; canal or groove (formed in 

 consequence of the closure or partial filling up of the slit 

 from time to time) deep and striated across ; the edges of the 

 slit and canal are somewhat thickened, sharp, and prominent : 

 mouth roundish, placed obliquely, ending in a small corner 

 at the upper part of the columella or pillar ; peristome con- 

 tinuous : outer lip thin : inner lip folded back on the colu- 

 mella : umbilicus deep, but exposing only the under side of 

 the last or body whorl : operculum filmy, having many ap- 

 parently concentric volutions in the central part, the last 

 being very large in proportion. L. 0-075. B. 0-1. 



Yar. paucicostafa. Spire more raised, and the ribs on the 

 upper side much fewer than usual. 



Habitat: Stony ground in Shetland, 18-75 f.; not un- 

 common. It lias also been taken by Captain Thomas abun- 

 dantly in 7 f. at Sanda Sound in the Orkney Isles ; more 

 sparingly by Mr. Peach at Wick, and in Dunnet Bay, 

 Caithness ; by Mr. Barlee at Skye and in other parts 

 of the west of Scotland ; by Mr. Hyndman in 27 f. on 

 the Antrim coast ; and by Captain Hoskyns in about 

 100 f. on a fishing-bank off the west of Ireland. The 



