360 



MANUAL or THE MOLLUSCA. 



Cytherea chione. 

 Petricola lithophaga. 

 Venerupis irus. 

 Cardium rusticum, L. (tu- 

 berculatum). 



7 bivalve shell -fish, are, at present only known in British seas ; but as most 

 of these are minute or "critical" species it is considerCil they will yet be met 

 with elsewhere. 



A few of the species belong to the Lusitauian province, whose northern 

 limits include the Channel Islands, and just impinge upon our coast. 

 Pbasiauella pullus. Murex corallinus. 



Haliotis tulierculata. Avicula Tarentina. 



Truncatella Moutagui. Galeomma Turtoni. 



Oncidium celticum. Pandora rostrata. 



Bulla hydatis Ervilia castanea. 



Volva patula. Mactra heivacea. 



Of the Gasteropoda 54 are common to the seas both north and south of 

 Britain; 52 range further south, but are not found northward of these 

 islands; and 34 which find here their southern limit occur not only in 

 Northern Europe, but most of them in Boreal America. Nearly half of the 

 bivalves range both north and south of Britain ; 40 extend southward only, 

 and about as many more are found in Scandinavia, 27 of them being common 

 to N. America. {Forbes.) 



In the lists of Arctic and Boreal shells the British species are distinguished 

 by an asterisk. 



According to "Mr. M'Andrew's estimate there are 406 British shell- 

 bearing mollusca, of which 



217 or 53 per ceut. are commou to Scandinavia. 

 246 or 61 „ „ North of Spain. 



227 or 56 „ „ S. Spain and Medit. 



97 or 24 „ „ Canary Islands. 



The following are at present peculiar to Britain : — 



Assiminea, sp. 

 JeflFreysia, sp. 

 Otina Otis. 

 Rissoa, sp. 

 Stylifer turtoni. 



Odostomia, 19 sp. ? 

 Buccinum fusiforme. 

 Fusus Berniciensis. 



„ Turtoni. 

 Natica Kingii. 



Montacuta ferruginosa. 

 Argiope cistellula. 

 Pecten niveus. 

 Syudosmya tenuis. 

 TLracia villosiuscula. 



Fusua antiquus. 

 Litorina litorea. 



The most common edible species are: — 

 Ostrea edulis. Mytilus edulis. 



Pecten maxiraus. Cardium edule. 



„ opercularis. Buccinum undatum. 



Amongst the species characteristic of the Celtic province — or most abua- 

 daut in it — are the following : — 



Trophon muricatus. 

 Nassa reticulata. 

 Natica INIoutagui. 



„ motiilifera. 



„ nitida. 

 Velutina laevigata. 

 Turritella communis. 

 Aporrhais pes-pelecani. 

 Rissoa cingillus. 

 *^calaria Trevelyana. 



Litorina litoralis. 

 Troclius Moutagui. 



,, millegranus. 



„ tumidus. 



Patella vulgata. 



„ pellucida. 

 Acmaea virginea. 

 Chiton ciuereus. 

 Scaphander lignarius. 

 Telliaa ci-assa. 



Venus stnatula. 



„ casiua. 

 Donax anatinus. 

 Solen ensis. 

 Pholas Candida. 

 Mactra elliptica. 



,, solida. 

 Periploma prsetenuis. 

 Thracia distorta. 

 Syndosmya prismatica. 



