SPECIES EXCLUDED. 291 



28t}i. In 1839, Mr. Edward Forbes and Mr. GooDsiRgave 

 me, for the Museum collection, from Guernsey — 

 1. Helix aperta. — 2. Helix revelata. 



29th. Mr. Bellamy, at the meeting of the British Association 

 (in 1841) at Plymouth, showed specimens of Helix revelata, dis- 

 covered near Mevagissey, Cornwall. 



30th. Mr. Alder, in the Annals and Magazine of Natural His- 

 tory for 1846, describes a new Scotch shell, Limnea Burnetti. 



31st. In 1856, Dr. Gray, in ihQAnnal. and Mag. Nat. Hist. 

 xvii. 466., and xviii. 25., describes two new British species of 

 Sphserium, found near London — 



1. Sphffirium pallidum. — 2. Sphasrium pisidioides. 



III. 



LIST OF SPECIES IMPROPERLY INSERTED IN THE BRITISH 

 FAUNA. 



Wishing to make the woi'k really what its title represents it, 

 the species described are restricted to those which appear to be 

 truly native. Only the two following, viz. 



Testacella haliotoidea., t. 3. f. 19., and 



Dreissena polymorpha, 

 have been admitted among those which are supposed to have 

 been introduced in modern times. These have been admitted, 

 because they are completely naturalised, and propagate them- 

 selves in our climate in the open air. Indeed it is doubtful 

 whether the first of them may not be as strictly native as several 

 other species commonly considered so ; such as. Helix pomatia, 

 H. holosericea, H. carthusiana, and H. pisana. 



Several other species were recorded and described in the 

 first edition of this work, which have been introduced with 

 foreign plants, either buried in the mould or on the plants 

 themselves, or which have most probably been brought to this 

 country in the egg state. These are not truly acclimatised, 

 and only propagate their species when they are kept in stoves 

 u 2 



