128 PYRAMIDELLID.E. 



i)VQ often visible outside : inner lip adhering to the pillar above 

 the tooth, and joining the outer lip at its upper angle, reflected 

 and curved below the tooth : iimhUiciis small but deep, partly- 

 covered by the reflexion of the inner lip : tooth strong, promi- 

 nent and conspicuous, placed just behind the umbilicus ; it 

 winds round the pillar from one end of the spire to the other, 

 like the worm of a corkscrew : operculum yellowish-brown, of 

 equal proportionate solidity with that of Cyclostoma elegaiis, 

 and exquisitely sculptured by close- set flexuous striae in the 

 line of growth ; it has a curved groove down the middle, which 

 ends in the spire of the operculum, and gives to the portion 

 thus separated in front a cornucopia-shape ; this groove is 

 deep and very distinct ; side-flap rnther broad, widening with 

 the growth of the operculum, and divided from the spiral part 

 by a narrow line. L. 0-25. B. 0-1. 



Var. australis. Smaller and narrower. 



Habitat : Coralline and deep-sea zones, in mud, from 

 25 to 80 f., throughout Shetland and Scotland; Isle of 

 Man (Forbes, as 0. plicata apparently) . It is locally 

 plentiful in the Clyde district and Hebrides. The variety 

 has a southern range, comprising the Channel Isles, 

 Dorset, Devon, Cornwall, Galway, and Cork ; in rock- 

 pools, Falmouth (Barlee, and Miss Vigurs, fide Cocks) ; 

 among Zoster a, Jersey (Dodd). This species Avas ori- 

 ginally described as a fossil by Brocchi from the Sub- 

 apennine tertiaries, and it has been recorded by Philippi 

 from basaltic tufa at Militello, by Nyst (as O. jjlicatd) 

 from Belgium, and by S carles Wood (under the latter 

 name) from our Coralline Crag ; the Rev. H. W. Cross- 

 key has found it in the Clyde beds, and M. Mace in an 

 upper miocene deposit near Antibes. The ordinary or 

 typical form inhabits the North Sea, from Hammerfest, 

 40 f (Sars), to Gottenburg, 12 f (Malm) ; and the variety 

 is distributed ahmg the European coasts of the Atlantic 

 from Brittany, in the laminarian zone (Cailliaud), to 

 Gibraltar, 8-30 f. (M^indrew), every part of the Medi- 



