162 THE ZOOLOGIST. 
I have seen the Grey Plover (S. helvetica) with Waders showing 
typical evolutions it has always separated from them at the 
beginning of flight, and when alone as a species it acts in a way 
similar to that of the Golden Plover (Charadrius pluvialis). I 
have not been able to decide from the descriptions I have read 
whether the genus Macrorhamphus shows typical evolutions, or 
the form represented by the Golden Plover. This genus is 
placed in the subfamily Scolopacine; in its habits it is said to 
resemble Limosa. From the information available to me regard- 
ing the family Charadriide, and bearing on this matter, I have 
ventured to set down a number of conditions, all of which are 
fulfilled by the birds known to me to show these movements. 
The birds are: (1) of small or moderate size; (2) of gentle dis- 
position; (3) those in which the upper parts are of a pale 
brown, pale grey, or pale brownish grey colour, and the lower 
parts more or less of a white colour in winter; (4) those which 
live in flocks in winter; (5) those which are regular inhabitants 
of the shore in winter. It is scarcely worth while at present 
to make out a list of the species of these birds. A greater 
desideratum would be to learn of exceptions and of the conditions 
which do not apply to them, and also of species which fulfil the 
conditions and yet have no evolutions. 
The evolutions of the genera named are built up, as it were, 
on a simpler form of movement generally characteristic of the 
whole family, and consisting of specifically swift flights in com- 
pact strings to windward and to leeward in horizontal planes. 
The Oystercatcher and the Curlew exhibit these simple move- 
ments. The Plovers (Charadrius) have added what I call the 
“reverse.” It consists of a sudden rotation of the body from 
one declination to the other about an imaginary antero-posterior 
axis passing through the body. When this takes place, as it 
often does, so that the pale lower parts are quickly exposed to 
the observer, an effect is produced on the retina as of a flash of 
light. Plovers show the “‘reverse”’ at irregular though frequent 
intervals. The evolutions proper are often very complex and 
bewildering, but there is a form of movement which I believe to 
be the keynote of all of them. Resting on the basis of the 
windward and leeward movements, it consists of a sudden 
upeast gradually slowing down, and then curving over into an 
