512 MR. J. S. HUXLEY ON THE 
combination, in various arrangements, of the shaking-bout, the 
Dundreary, the Cat, the Ghost-dive, the weed-trick, and the 
Penguin-dance; in addition, they may be slightly modified by 
jealousy. ; 
They can be divided into two groups: (1) those in which the 
Cat-position plays a prominent part, and (2) those into which 
weed-carrying enters. Let us consider them in this order. 
The Cit-position forms a part of two quite distinct ceremonies, 
which, simply for the sake of ready reference, I shall cali the Cere- 
mony of Discovery and the Display. he first of these is gone 
through, as far as I can make out, when the two birds of a pair 
find and rejoin each other after being separated for some time. 
‘The second always occurs in the middle of a bout of shaking; on 
such occasions I presume that the shaking has not been ‘self- 
exhausting,’ but that the emotional excitement that accompanies 
it has reached a slightly higher level than usual, with the result 
that it overflows into a new nervous channel, and so expresses 
itself in this new way. 
(b) The Ceremony of Discovery.—A typical case has already 
been described (p. 497). I should interpret the facts thus :——The 
two birds of a pair have become separated—perhaps they have 
gone off fishing in different directions, or one has been on the 
nest and the other has not stayed near by. ‘They wish to rejoin 
each other. ‘l'o this end the bird that is searching puts itself into 
a special attitude, which is probably adapted for uttering the 
special ery only heard on such occasions, and cruises about, alter- 
nating its signal-calls with moments of looking about it. On 
hearing the call, several neighbouring birds will usually prick 
up their necks and look about them; but I believe that it is 
usually only the searehing bird’s true mate who takesany further 
interest (this would doubtless depend on the emotional state of the 
neighbouring birds), Once this discovery of the missing mate has 
been made, a special ceremony takes place to celebrate the event. 
This ceremony is a peculiar one, and is practically confined to these 
occasions of discovery ; very possibly the memory of the ceremony 
and its excitement adds to the eagerness felt by one bird of a pair 
to rejoin the other. The ceremony itself usually consists in 
this—the bird has been discovered dives, upon which the 
searcher puts itself into what I have called the Cat-attitude, a 
bizarre but beautiful position obviously recalling the elaborate 
displays of many other birds. In this attitude the searcher waits, 
almost always in a state of great excitement, as shown by its 
turning itself hither and thither, from side to side. Jt is stimu- 
lated to this excitement by the diving bird: first of all, as the 
dive is very shallow, the diver’s approach is marked by a swift 
vipple of the surface ; and then, when the diver at length appears, 
it 18 in a shape as unlike that of everyday life as is the “ Cat- 
position ” of the searcher—albeit the two are at opposite poles of 
the Grebe’s capabilities, Sometimes the diver emerges when only 
