262 CERITHIID.E. 



than either of the other two, and high up on the spire this 

 is always the case, preparatory to the middle row being 

 squeezed out or disappearing ; the base of the shell is girded 

 by 3 strong spiral ridges, two just below the periphery, and 

 the third very short and winding obliquely round the senritu- 

 bular and recurved groove or fluting at the extreme base ; the 

 uppermost of the basal ridges is occasionally beaded : colour 

 dark chestnut, fading into yellowish-brown ; tubercles mostly 

 of a lighter hue : spire tapering to a fine point ; apex as in the 

 last species, but reversed : whorls 15-16, compressed, gradually 

 enlarging ; the last nearly equals one-third of the shell : suture 

 narrowly excavated : mouth squarish ; groove narrow and deep, 

 turning abruptly to the right ; it is nearly closed above, in 

 consequence of the inner lip overlapping one side of the groove 

 and of the outer lip being contracted into a small but deep 

 sinus on the other side ; the relative length of the mouth is 

 the same as in the last species : outer lip semicircular and pro- 

 minent, slightly reflected in the middle, having the upper and 

 lower corners contracted into a small and deep sinus or inden- 

 tation, and considerably retreating on the upper side where it 

 joins the periphery; edge scalloped by the spiral ridges; inside 

 smooth : inner lip broad, forming a thick pad or deposit on the 

 pillar, with which it makes an obtuse angle ; this lip is united 

 with the other at the upper corner of the mouth : pillar short, 

 strong, and curved : operculum rather thin, obliquely and 

 irregularly striated; spire small, indistinct, with a circular 

 and many-whorled nucleus. L. 0*35. B. 0*1. 



Var. pallescens. "Whitish, faintly tinged with yellowish- 

 brown. 



Habitat : Southern and western coasts of England 

 and Wales, the Channel Isles, and all Ireland ; Sand- 

 wich (Walker and J. G. J.) ; Clyde district (Smith and 

 Norman); Dunbar (Laskey); Aberdeenshire (Dawson); 

 Caithness (Gordon); Orkneys (Forbes and M' Andrew); 

 Shetland (F. & H.). Not uncommon in the lower part 

 of the littoral zone, and down to the coralline. I dredged 

 the variety at Guernsey. Italian tertiaries (Brocchi and 

 Philippi); Irish beds (Smith); Coralline Crag (S.Wood); 

 post-glacial formation in Norway, 120 feet (Sars) . The 

 present distribution of the larger or typical form ranges 



