PREFACE. Xl 
Gull (Larus ridibundus of this work, vol. iii. page 550,) 
by having a smaller and weaker bill, shorter tarsus and 
toes, as well as interdigital membranes of less extent. M. 
Temminck has for a long time possessed one example 
brought by a whaler. It has been met with in Scotland. 
M. Bruch has observed it many seasons in succession, 
about the period of its migration, on the banks of the 
Rhine ; he tells me that it arrives there before the Laugh- 
ing Gull, from which he distinguishes it by a slight differ- 
ence in the voice. The Marquis of Durazzo has received 
one specimen that was killed in the vicinity of Genoa, and 
M. de Feldegg brought one from Dalmatia. M. Verreaux 
sent us one specimen from the Cape of Good Hope: it has 
been killed near Dunkirk, and on the coast of Holland. 
These facts seem in favour of the opinion that this Gull 
is of a particular race, different from the Laughing Gull. 
It appears, however, that these two races sometimes pair 
one with the other, or that they breed in company, 
because I killed in the summer of 1843, upon a lake 
near Leyden, two pair of Gulls that were nesting there, 
one male bearing all the characters of the true L. ridi- 
bundus, while the female belonged to the small race of this 
species.” 
The next observations are copied from the printed Pro- 
ceedings of the Zoological Society for May 27th, 1845 : 
“Mr. Thompson of Belfast read a paper to prove that 
the Larus capistratus, Temm., is not a distinct species 
from L. ridibundus, and exhibited a series of specimens 
of both forms in different states of plumage obtained in 
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