INTRODUCTION. XIX 



cite AcmeEa mrcfmea^ Astarte sulcata, Buccinum undatum, 

 Chiton cinereus and ruber, Crenella decussata and discors, 

 Fusus antiquus and Islandicus ; the various species of 

 Lacuna, Littorina littoralis, littorea and rudis, Lucina 

 horealis, Mactra elUptica and solida, Blangelia turricula, 

 Modiola modiolus, Mya arenaria and tnmcata, Mytilus 

 edulis, Natica monilifera, Nassa incrassata, Ostrea edulis, 

 Patella pellucida, Pecten maximus, Pholas crispata and 

 Candida, Purpura lapillus, Rissoa cingillus and striata, 

 Saxicava arctica and rugosa. Scaphander lignarius, Skenea 

 planorhis, Solen ensis, Syndosmya prismatica. Tapes pul- 

 lastra, Thracia disiorta, Trophon clathratus and muricatus, 

 Velutina Icevigata and Venus casina. Many of our naked 

 Mollusks take their place here. 



V, Peculiarly British may be styled the assemblage of 

 species little known elsewhere, or even unknown out of our 

 own seas. The list is considerable but very fallacious, 

 since it is SAvelled by minute or critical forms, that in all 

 probability enjoy a wider range, but have as yet escaped 

 observation on stranger shores. In this category we may 

 place many of the Odostomioe and JSIontacutce, hitherto un- 

 recognised on other coasts than our own. Every year dis- 

 covers that the parentage of some cherished species is not 

 so exclusively British as patriotic naturalists fondly ima- 

 gined. Excluding, however, ail critical types or forms 

 liable from resemblance to others to be overlooked, the 

 following remarkable Testacea have not as yet been no- 

 ticed beyond our limits : — Assiminea Grayana, Astarte cre- 

 hricostata (probably arctic), Buccinum fusiforme, Fusus 

 Berniciensis, Fusus Turtoni (the three last will probably 

 prove to be members of a more northern Fauna) ; the species 

 of Jeffreysia, L&pton ClarJcicc, Megathyris cistellula, Natica 

 Kingii (probably arctic) ; Otina otis, Pecten niveus. Pro- 



