* CERITHIOPSIS. 267 



becomes suddenly very much narrower, and consists of 4 or 5 

 whorls ; apex twisted a little downwards : luTiorh 13-14, com- 

 pressed, the last exceeds one-third of the shell : suture nar- 

 rowly channelled : mov.th oval, truncated at the base ; its 

 leug-th, with respect to 'that of the spire, is as 2 to 7 : ccmal 

 liearly tubular, and exhibiting outside a deep and rounded 

 notch at the base — quite different from what appears in any 

 species of Cerithium : outer lip semicircular and rather promi- 

 nent, having a thick edge, which is scalloped by the spiral 

 ridges ; inside smooth ; this lip is contracted at the upper cor- 

 ner of the mouth into a smaU sinus (formed by an indentation 

 of one of the ridges), but it does not retreat or slope backwards 

 as in Cerlth ium perversum : inner lip rather broad, forming a 

 rather thick fold on the lower part of the pillar, and continu- 

 ous with the outer lip at the upper corner : pillar extremely 

 short, and nearly straight : operculum thin, marked Avith very 

 delicate and minute ilexuous striaj ; spire excentric, minute. 

 L. 0-25. B. 0-085. 



Yar. nana. Dwarf and spindle-shaped. (Is this the male ?) 



Monstr. Clarlii. Lower and middle whorls having but two 

 rows of tubercles, all of which are oblong ; the earlier whorls 

 have the usual number of rows. 



Habitat : Under stones in the lower part of the lit- 

 toral zone^ and hard ground in the laminarian and 

 coralline zones^ along our southern and western coasts, 

 including the Channel Isles, Bristol Channel^ and St. 

 George^s Channel, all Ireland, the west of Scotland, and 

 Shetland ; Sandwich {Boys, fide Montagu) . The variety 

 is from Guernsey, Bantry Bay, and other places. The 

 monstrosity was taken by Mr. Clark at Exmouth, and 

 by me at Guernsey. Fossil : '' Ireland ; Clyde '^ (J. 

 Smith) ; Coralline Crag at Sutton (Wood) ; Belgian ter- 

 tiaries (Nyst). Its extra-British habitat ranges from 

 Christiansund (Lilljeborg), southward to Fayal in the 

 Azores (Drouet), and throughout the Mediterranean 

 and Adriatic, at depths of from ]0 to 60 f. ; Charlestown 

 Harbour in South Carolina (C. B. Adams, as Cerithium 

 Greenei) . Malm found a specimen of the monstrosity 



