SPECIES EXCLUDED. 
291 
28th. In 1839, Mr. Edward Forbes and Mr. GooDsiRgave 
me, for the Museum collection, from Guernsey — 
1. Helix aperta. — 2. Helix revelata. 
29 th. 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 iheAnnal. and Mag, Nat Hist 
xvii. 466., and xviii. 25., describes two new British species of 
Sphgerium, found near London — 
1. Sphaerium pallidum. — 2. Sphserium pisidioides. 
III. 
LIST OF SPECIES IMPROPERLY INSERTED IN THE BRITISH 
FAUNA. 
Wishing to make the work 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 
