FISSURELLA. 267 



Habitat : South-eastern, southern, and western coasts 

 of England (including the Channel Isles), Bristol Chan- 

 nel, Isle of Man, Anglesea, all around Ireland, and the 

 west of Scotland; not uncommon in oj^ster beds and 

 on old shells and rocks, from low-water mark to 50 f. : 

 Caithness coast (Gordon); Orkneys (Thomas); and 

 Forbes gives it, in his report to the British Association 

 for 1850, as living at 10 f. in Shetland. It occurs fossil 

 at Moel Tryfaen (Darbishire); Red and Coralline Crag 

 (S. Wood); as well as in the Belgian, French, and Italian 

 tertiaries. South of Great Britain it has a wide distri- 

 bution in a recent state, as far as the ^Egean and 

 Canaries, at depths ranging from the shore-line to 95 f. 

 I am not aware of any northern locality. 



Petiver called this the "thimble limpet,^^ possibly 

 from its being open at the top, like a tailor^s thimble. 

 The number of longitudinal ribs, and consequent com- 

 pactness of the cancellation, vary greatly; in a specimen 

 fi'om Guernsey I counted no less than seventy-two of 

 these ribs. 



The only habitat assigned by Linne to his Patella 

 grceca was the Mediterranean. His description, al- 

 though short, suits our shell; and his references, with 

 the exception of Adanson (and perhaps also of Gualtieri 

 and Kegenfass) , are quite appropriate. Our shell is the 

 P. larva, reticulata (in the index P. reticulata) of Da 

 Costa, F. cancellata, Gray (but not of G. B. Sowerby), 

 F. EuropcEa, Sowerby, F. occitanica, Becluz, and F. Lis- 

 teri, Woodward ; the fry is P. apertura, Montagu, Sipho 

 radiata, Brown, F. striata, Becluz, and Cemoria Monta- 

 guana, Leach. 



I have a worn specimen of F. nubecula, Linne, in 

 Turton^s collection, which, he states (in his 'Concho- 

 logical Dictionary^), had been dredged off the Land^s 



n2 



