NOTES—ORIGINAL AND SELECTED. 121
expressed his belief that the habit was common, more or less, to
all, or almost all, birds, but particularly to those who fed on
grain, mice, fish, insects having hard outer coats, and similar
foods. In none was the pellet-forming habit better known than
among the Owls, the contents of whose pellets had often been
investigated and described.
Mr. Christy added that he was interested in Miss Lister's
statement that the india-rubber rings from the necks of ginger-
beer bottles were found in abundance beneath the trees in which
rooks roosted in Wanstead Park, having been ejected by the
rooks in their pellets; for he had observed and recorded (Birds of
Essex, p. 135) exactly the same thing in Mr. Round's woods at
Birch, beneath trees in which many rooks roosted. In this case, no
doubt, the birds had collected the rings from the town manure
spread on the fields around the town of Colchester, from which
Birch is distant only four miles.
Mr. W. H. Dalton, F.G.S., suggested that this habit of
pellet-casting by rooks, starlings, and other birds, might afford
an explanation of the occurrence of Marine or Estuarine Mol-
lusca, both recent and semi-fossil, in inland localities. The
birds, in feeding on the shores or estuarine marshes, would
swallow the shells and then cast them up on visiting the
uplands.
Mr. Jonathan Seabrooke confirmed some of Miss Lister's
observations. He had often seen pellets contain portions of
rubber rings in his garden at Grays. At first, he was disposed to
think that the rooks cast up pellets at the nesting period only,
but later observations had shown that these pellets were to be
found tinder the nests long before there were young.
. PLANTS.
Introduction and Habitats of Claytonia perfoliata
in Essex.—At the meeting on 30th October, Mr. J. C.
Shenstone, F.L.S., made some interesting remarks in this
connection. He said:— "Alien plants and 'casuals' are
well worth watching, as interesting information, showing how
casuals in time adapt themselves and become established,
might be discovered. I illustrate this by instancing Claytonia
perfoliata, which was originally an escape from a garden at West
Bergholt, Colchester. After leading a casual existence on